Oral Mucous Membrane

Oral mucous membrane

Dr. Kush Pathak

CONTENTS Introduction Definition Classification Development of oral mucosa Functions Clinical features Components of oral mucosa Oral epithelium/ Epidermis Epithelial proliferation Epithelial maturation Non keratinocytes Ultra Structure of Epithelial cell Lamina Propria/ Dermis

Submucosa Arterial blood supply of oral mucosa Nerve supply of oral mucosa Tongue Junctions in oral mucosa Gingiva Fibers of gingiva Age changes in oral mucous membrane Clinical considerations Conclusion

Introduction

The skin, oral mucosa and intestinal lining, all consist

of two separate tissue components, which are, the

covering epithelium and an underlying connective

tissue. As these tissues, together perform a common

function, the oral mucosa must be considered as an

organ.

Understanding the complex structure of a tissue or

organ often is easier, when it’s function is known. The

structure of oral mucosa reflects a variety of

functional adaptations. Any change in these

functional adaptations, leads to pathology.

Definition :

“The term moist membrane is used to describe moist lining of GIT, nasal passages and other body cavities that communicate with exterior. In the oral cavity this lining is called oral mucous membrane.”

Classification

(A) Based on functional criteria : (1) Masticatory mucosa : Gingiva and hard palate

(2) Lining / reflecting mucosa : lip, cheek, soft palate, floor of mouth.

(3) Specialized mucosa : Dorsum of tongue

(B) Based on structure of surface layers :

(1) Keratinized mucosa : Hard palate and gingiva

(2) Non keratinized mucosa : Cheek, soft palate, vestibule, floor of mouth etc.

Development of oral mucosa

At about 26 days of gestation - Primitive oral cavity develops by fusion of embryonic stomatodeum with foregut, after rupture of buccopharyngeal membrane and thus gets lined by epithelium derived from ectoderm and endoderm.

Tongue, epiglottis and pharynx are covered by epithelium derived from endoderm, whereas epithelium covering the palate, cheeks, and gingiva is derived from ectodermal origin.

By 5 to 6 weeks of gestation – single layer of cells lining the primitive oral cavity, has formed 2 cell layers.

Initially ectomesenchyme consists of widely spaced stellate cells in an amorphous matrix, but by 6 to 8 weeks, extra cellular reticular fibers begin to accumulate.

At about 7weeks- Circumvallate, foliate and fungiform papillae develop on the lingual epithelia.

By 8 weeks – Thickening occurs in the region of vestibular dental lamina complex.

At about 8 to 11 weeks.- palatal shelves devate and close.

By 8 to 12 weeks, capillary buds and collagen fibers can be detected.

At about 10 weeks filiform papillae become apparent.

By 10 to 12 weeks- future lining of masticatory mucosa show some stratification of epithelium.

By 10 to 14 weeks -Cellular degeneration occurs in central region of the thickening of vestibular dental lamina complex.

Between 13 to 20 weeks- all oral epithelium thicken and with the appearance of keratohyalin granules, so a distinction between prickle and granular layer can be made.

Between 17 to 20 weeks – elastic fibers become prominent only in connective tissue of lining mucosa.

Functions : Protection : Separates and protects deeper tissues

and organs from mechanical stresses/ forces, and external environment.

Sensation : Temperature, touch and pain sensation. Tongue has taste buds. Reflexes like swallowing, gagging, salivating, also are initiated by receptors in oral mucosa.

Secretion : Saliva is secreted by salivary glands and contributes to the maintenance of a moist surface.

Thermal regulation : In some animals (dog), considerable body heat is dissipated through oral mucosa by panting. For these animals, oral mucosa plays a major role in regulating of body temperature. This function is not active in humans.

Absorption : Certain substances like nitrates are absorbed from sublingual region.

Excretion : Excretes metabolites.

Aesthetics : Gingiva and lip mucosa enhance facial esthetics.

Clinical features of oral mucosa: Deeply colored, most obviously at the lips.

Contains only minor salivary glands in comparison to skin that contains hair follicles, sebaceous glands and sweat glands.

Surface of oral mucosa tends to be smoother and have fewer folds or wrinkles than skin.

Healthy gingiva shows fine surface stippling (small indentations on mucosa surface).

Slight whitish ridge present on the buccal surface is called linea alba (white line). It is a keratinized region and may represent the effect of abrasion from rough tooth restorations or cheek biting.

Components of oral mucosa Oral mucosa consists of 2 separate tissue

components :

(1) Epidermis - Stratified squamous epithelium, called oral epithelium.(2) Dermis – Underlying connective tissue , called lamina propria.Upward projections of connective tissue into epithelium, are called connective tissue papilla.Epithelium is formed into ridges that protrude towards lamina propria. These ridges are called epithelial ridges.At their junction there are 2 different structures with very similar names : (1)Basal lamina (2)Basement membrane

(1) Basal lamina : It is evident at the electron microscopic level and is epithelial in origin. It has two parts : lamina lucida and lamina densa.

(2) Basement membrane : It is evident at light microscopic level and is found at the interface of epithelial and connective tissue within the connective tissue.- It is 1 to 4 µm wide.- It is cell free. -Stains positively with PAS, indicating that it contains neutral mucopolysaccarides.-In skin it is shown to contain Fibronectin, laminin (glycoproteins), heparin sulfate, proteoglycans, type 4 collagen and some antigens.

Oral epithelium/ Epidermis

It is a Stratified Squamous epithelium consisting of cells tightly attached to each other and arranged in a number of distinct layers or strata.

It maintains it’s structural integrity by a process of continuous cell renewal in which, cells produced by mitotic division in the deepest layers, migrate to the surface to replace those that are shed.

The cells of the epithelium thus can be considered to consist of two functional populations :

(1) Progenitor population : Its function is to divide and provide new cells.

(2) Maturing population : The cells which continually undergo a process of maturation to form a protective surface layer.

Epithelial Proliferation Progenitor cells are situated in basal layer in thin

epithelia (e.g. Floor of mouth) and in lower two or three cell layer in thick epithelia.

Dividing cells are present in clusters at the bottom of epithelial ridges.

A small population of progenitor cells represent stem cells. Function of these stem cells is to produce basal cells and retain proliferative potential of the tissues.

Large portion of the progenitor compartment is composed of amplifying cells. Their function is to increase the no. of cells available for subsequent maturation.

After cell division, each daughter cell recycles in the progenitor population and enters the maturing compartment.

Epithelial maturation

There are two main patterns of maturation : (1) Keratinization

(2)Non-Keratinization

(1) Keratinization :Keratinized epithelium has following layers : (a) Stratum basale(b) Stratum spinosum(c) Stratum Granulosum(d) Stratum corneum.

Click icon to add picture

Layers of oral mucosa

Stratum basale They are present above the basement membrane. They have cuboidal or columnar cells. Cells of the basal layer shows most mitotic activity. This layer is also called Germinative layer. They are attached to the basement membrane by

hemidesmosomal junction.

Stratum Spinosum

Present just above the basal layer. Arranged in several rows. Cells are larger elliptical or spherical in shape and are

known as Prickle cell layer. Cells are fused together due to the presence of

intercellular bridges or desmosomes. In the upper part of this layer, membrane coating

granules/ lamellate granules/odland bodies are present. These granules are small, membrane bound structures. They are 250nm in size. They contain glycolipids originating from golgi complex.

Stratum spinosum

Stratum spinosum Cells of stratum spinosum

Stratum Granulosum

Present just above the spinous layer. Cells are large and flattened containing small granules. These granules are Keratohyaline granules and layer is called

granular layer. Cells in the superficial part of this layer develop a noticeable

thickening on the inner(intracellular) aspect of their membrane, that contributes to the considerable resistance of keratinized layer against chemical solvent. This thickening is due to protein known as involucrin.

Membrane coating granules are present and they appear to fuse with superficial cell membrane to discharge their content in the intercellular space.

This discharge is associated with formation of lipid rich permeability barrier, that limits the movement of aqueous substance through intercellular spaces.

Stratum granulosum

Stratum granulosum

Cells

Stratum Corneum Consists of squames or flat cells. They do not contain any nuclei. They stain bright pink with eosin as they are eosinophilic. Pattern of maturation of these cells often is termed as

ORTHOKERATINISATION. In Parakeratinised epithelium, surface layer stains for

keratin, but shrunken (pyknotic) nuclei are retained in many squames/ flat cells.

Orth

okra

tinizd

Stra

tified

Squam

ous e

pith

eliu

mPa

rake

ratin

ized e

pith

eliu

m

of g

ingiv

a

As the cells of the granular layer reach the junction with the keratin layer, sudden changes in appearance occur, with loss of nuclei, organelles and Keratohyaline granules.

Cells get dehydrated and take up hexagonal shape called Squames.

Keratinized layer in oral cavity is composed of nearly 20 layers of squames. .

Incomplete Keratinization/ Parakeratinisation : Outer most squames of keratinized or Parakeratinised layer do not look like rest of the keratin but show a staining similar to that of deeper nuclear cells. This is called Incomplete Keratinization.

(2) Non- Keratinization :

Layers of non keratinized epithelium are :

(a) Stratum basale (b) Stratum intermedium(c) Stratum superficial / stratum distendum(mechanically

flexible)

Stratum basale

This layer is similar to that of keratinized

epithelium.

Only difference is that the cells of this layer in

non keratinized epithelium are slightly larger

than that of keratinized epithelium.

Intercellular bridges are less conspicuous.

Stratum Intermedium

Glycogen is present

Rarely keratohyaline granules are also visible at this level, but

they are not associated with tonofilaments.

Membrane coating granules are present and they appear to be

circular in shape with an amorphous core.

Granules discharge their content in the intercellular spaces.

But the contents have different lipid composition and do not

form as effective barrier for aqueous substances as

keratinized epithelium.

FILLAGRIN is absent.

LORICRIN is present and may contribute to internal thickening

of cell membrane.

Stratum Superficiale

Cells appear slightly more flattened than other

layers.

They contain dispersed tonofilaments and nuclei

and dehydrated cells.

This surface is flexible and tolerant to

compression and distension.

Non-Keratinocytes

Cells that contain clear halo around the nuclei are

caller clear cells .These cells are glycogen abundant

and so they don’t get stained by Hematoxylin and

eosin. Thus resulting in a clear cytoplasm. They are

collectively known as Non keratinocytes.

They are :

(a) Melanocytes

(b) Merkel cells

(c) Langerhan’s cells

(d) Inflammatory cells (lymphocytes)

1. Melanocytes : Present in basal layers. These cells contain dendrites. No desmosomes and filaments. Premelanosomes and melanosomes are present. Functions : Synthesizes melanin pigment granules (melanosomes)

and transfer to surrounding keratinocytes. Thus, it causes endogenous pigmentation of oral mucosa.

2. Langerhan’s cells : Present predominantly in suprabasal layer Small rod or flask shaped granules called Birbeck granules

present. Dendrites present. No desmosomes and tonofilaments.

Functions : Antigen trapping and processing.

3.Merkel cells : Present in basal layer. No dendrites present. Desmosomes and tonofilaments present. Characteristic electron dense vesicles and associated

nerve axon present.

Function : It is a tactile sensory cell.

4. Lymphocytes(Inflammatory cell) : Present variably. Contains large circular nucleus. Cytoplasm is scanty with few organelles. No desmosomes and tonofilaments present.

Function : Associated with inflammatory response in oral mucosa.

Ultra structure of Epithelial cell

Along with all cell organelles (nuclei, endoplasmic reticulum, ribosomes, mitochondria, golgi complex) , cells also contain certain structures :

Tonofilaments Desmosomes Hemidesmosomes Keratohyalin granules Keratin

Tonofilaments

They are fibrous proteins and are seen as long filaments.

Synthesized by ribosomes.

Diameter is approximately 8nm.

They belong to a class of intracellular elements called intermediate filaments.

They are intimately associated with keratohyalin granules.

Desmosomes

Also called macula adherens.

Circular or oval areas of adjacent cell membranes, adhering by specialized intracellular thickenings known as attachment plaques.

It consists of 2 proteins :- Desmoplakin and Plakoglobin.

Bundles of tonofilaments get inserted into these attachment plaques.

Proteins naming Cadherins (Desmoglein and Desmocollin), penetrate the membrane and enter the intercellular region of desmosome.

Hemidesmosomes

Adhesion between epithelium and connective tissue is provided by hemidesmosomes.

Hemidesmosomes are present on the basement membrane of the epithelium.

Tonofilaments get inserted in hemidesmosomes also.

Keratins

Keratins are classified according to their size (i.e. molecular weight) and charge.

Different types of keratin are present in different cells and even in different layers of a single stratified epithelium.

When they become aggregated, they form bundles of filaments called tonofibrils.

Keratins represent 30 different proteins of differing molecular weights.

Those with lowest molecular weight (40 kDa) are found in glandular and simple epithelia.

Those with intermediate molecular weight are found in stratified epithelium.

Those with highest molecular weight (67 kDa) are found in keratinized stratified squamous epithelium.

All stratified oral epithelium possess keratin 5 and 14.

All keratinized stratified oral epithelium contain keratins 1,6,10 and 16.

All non keratinized epithelium contain keratins 4, 13 and 19.

Keratohyalin granules Keratohyalin granules appear as basophilic granules

under light microscopy and as electron dense structures in electron microscopy.

Granules are irregular in shape.

Their size is 0.5 to 1nm.

They are synthesized by ribosomes.

They are associated intimately with Tonofibrils and are thought to facilitate aggregation and formation of cross links between the cytokeratin filament of keratinized layer.

For this reason, protein making up bulk of these granules are called FILAGGRIN.

Sulfur rich component called LORICRIN also occurs.

Two other type of connections are seen between cells:

Gap junction or ‘nexus’ – Region where membranes of adjacent cells run closely together, separated by only a small gap.Such junctions may allow electrical or chemical communication between cells and are sometimes called ‘Communicating Junctions’.

Tight Junction – Also called ‘Occluding junctions’. Here adjacent cell membranes are so tightly joined to each

other, that there is no intercellular space left. It is very rarely found.

Lamina Propria Connective tissue supporting the oral epithelium is termed

as Lamina propria. It is divided into 2 layers : Superficial papillary layer (associated with epithelial

ridges) : Here, collagen fibers are thin and loosely arranged.

Deeper reticular layer (lies between papillary layer and underlying structures) : This layer has collagen fibers arranged in thick bundles that tend to lie parallel to the surface plane.

Lamina propria consists of cells, blood vessels, neural

elements and fibers embedded. Cells of Connective tissue : 1. FIBROBLASTS - They are stellate or elongated cells with abundant

endoplasmic reticulum. They secrete fibers and ground substance. They are disturbed throughout the lamina propria.

2. HISTIOCYTES – Spindle or stellate shaped cells. They contain dark staining nuclei. Contain abundant Lysosomal vesicles. They are precursors of functional macrophages. They are present throughout the lamina propria.

3. MACROPHAGES – They are round with pale staining nucleus. Contain lysosomes and phagocytic vesicles. Helps in phagocytosis. Present in areas of chronic inflammation.

4. MAST CELLS – They are round cells with basophilic granules. They stain metachromatically. Secretes inflammatory mediators. Present throughout the lamina propria.

5. PMN CELLS – They are round with lobed nucleus. Helps in phagocytosis. Present in areas of acute inflammation.

6. LYMPHOCYTES – They are round with dark staining nucleus and scanty cytoplasm. They help in humoral and cell mediated immunity. Found in areas of chronic inflammation.

7. PLASMA CELL – They have cart wheel pattern with basophilic nucleus. They contain abundant rough endoplasmic reticulum. Helps in synthesis of immunoglobulins. Seen in areas of chronic inflammation.

8. ENDOTHELIAL CELLS – Present in lining of the blood Vessel.

Submucosa

High concentration of blood vessels and nerves are present.

It is a site of the minor salivary glands.

In the intestine the submucosa is called the muscularis mucosae

There is no such thing in oral mucosa.

In cheeks, lips and part of the hard palate – submucosa layer is made of loose areolar or adipose tissue

In regions such as gingiva and part of the hard palate, the submucosa is not present and the oral mucosa attaches directly to the periosteum of underlying bone. This is called mucoperiosteum

Arterial blood supply of oral mucosa

Hard palate - Major palatine artery. Nasopalatine artery. Sphenopalatine artery.

Soft palate : Minor palatine artery

Floor of mouth : Sublingual artery Branch of lingual artery

Tongue : Deep lingual artery . Dorsal lingual artery.

Nerve supply of oral mucosa

Hard palate: Greater palatine Lesser palatine Sphenopalatine branches of maxillary nerve.

Soft palate : Lesser palatine branch of maxillary nerve Nerve of pterygoid canal

Tongue : Lingual branch of mandibular nerve Glossopharyngeal nerve.

Tongue Mucosa of dorsal surface of the tongue, although covered by what

is functionally a masticatory mucosa, has different types of lingual papillae.

Some of these papillae possess mechanical functions, whereas some bare taste buds, therefore having sensory function.

Following papillae's are present on the tongue :

Fungiform papillae Filiform papillae Foliate papillae Circumvallate papillae

Fungiform papillae : Present on the anterior portion of the tongue along with

Filiform papillae.

Single Fungiform papillae is surrounded by numerous filiform papillaes at the tip of the tongue.

They are smooth and round structures.

They appear red, because of their highly vascular connective tissue core.

Present on the superior surface.

FUNGI

FORM

PAPI

LLAE

A : Fungiform papillaB : Filiform papillaeD : Heavy Keratinization

Filiform papillae : Cover entire anterior part

Consist of cone shaped structures, each covered by a thick keratinized epithelium.

Together form a tough, abrasive surface that is involved in compressing and breaking the food.

Dorsal mucosa functions as masticatory mucosa.

Filifo

rm P

ap

illae

Tiny P

roje

ctions

Histo

logica

l appeara

nce

Foliate papillae : leaf like.

Sometimes present on lateral margins of posterior part of tongue.

Pink papillae with 4 to 11 parallel ridges with deep grooves in mucosa.

Few taste buds are present in the epithelium of lateral walls of ridges.

Seen in mammals, not in human beings.

Folia

te P

ap

illae

Histo

logica

l appeara

nce

Ele

vatio

ns :- fo

liate

papilla

e

Circumvallate papillae : Present adjacent and anterior to the sulcus terminalis.

They are 8 to 12 in number.

Large structures, each surrounded by a deep, circular groove into which ducts of minor salivary glands (glands of von ebner)open.

Superiorly, connective tissue core of these papillae is covered with keratinized epithelium, whereas on lateral walls, it is covered with non keratinized epithelium.

Taste buds are present on the lateral walls.

CI

RCUMVALLAT

E

PAPI

LLAE

Taste Buds

It is composed of two types of cells, neuroepithelial and supporting (sustentacular) cells.

The neuroepithelial cells communicate with the free surface of the mucosa by the taste canal.

- Microvilli ("taste hairs") project from the ends of the neuroepithelial cells into the taste canal.

- The neuroepithelial cells are usually located centrally in the structure, surrounded by their supporting or sustentacular cells.

Taste

bu

ds

A :- Ta

ste b

uds

B :- M

icrovilli (ta

ste h

airs)

Papillae are mainly concerned with different taste sensations :

Vallate papillae : Bitter Fungiform papillae : Sweet and salty Foliate papillae : Sour

Junctions in oral mucosaA. Mucocutaneous junction : Junction between skin and mucosa. At this junction, few sebaceous glands are present. Epithelium is keratinized but thin. Red in color (vermilion zone) due to close proximity with blood. No salivary gland are there in the vermilion zone and only few sebaceous

glands are present, so it tends to dry out and cracked in winters.

B. Mucogingival junction :

Junction between gingiva and alveolar mucosa.

Histologically, a change occurs in this junction, not only in type of epithelium but also in composition of the lamina propria.

Stippling is seen, and reflects the attachment of the collagen fibers.

C. Dentogingival Junction :

Region where oral mucosa meets the surface of the tooth is called dentogingival junction.

Junctional Epithelium The junctional epithelium is that epithelium which lies

at, the base of the gingival sulcus. It attaches to the surface of the tooth with hemidesmosomes.

It is 1mm in width.

Cells in the junctional epithelium tend to have wide intercellular spaces, to allow the transmission of W.B.C’s from blood vessels to bottom of the

gingival sulcus, to help prevent the disease.

Its irregular in texture.

Gingiva

Tissue which covers the alveolus and encircles the neck of teeth is called gingiva.

Functions : Surrounds and supports the teeth. Prevents invasion of bacteria to periodontal ligament.

Parts of Gingiva : Free gingiva (Marginal or unattached) Attached gingiva Interdental papilla

Free gingiva :

Knife edge part of gingiva.

In normal healthy individual, width is about 1mm.

Causes food lodgment, when knife edge is thickened.

Attached gingiva :

Part which is firmly bound to periosteum is called attached gingiva.

Superiorly, it is bound to free gingival groove and inferiorly extends up to mucogingival line.

It is firm and reselient.

It’s width is maximum in maxillary incisor region :- 3.5 to 4.5 mm

It’s width is minimum in mandibular 1st premolar region :- 1.8mm

Increase in width of attached gingiva is due to supra eruption of a tooth with increased cementum deposition.

Any decrease in width is pathological.

Interdental Papillae :

Part which extends between two teeth up to the contact point is called interdental papillae.

It has a ‘facial side’ and a ‘lingual side’ .

It’s margins are concave.

Due to inflammation, interdental papillae looses it’s concavity.

COL : Connecting facial and lingual side of the interdental papilla (on

proximal side) is an epithelial structure called COL.

It’s concave shape means, gingiva is healthy.

It becomes dome shaped, in gingival recession and inflammation.

It is covered by non keratinized stratified squamous mucosa.

Fibers in gingiva :

Dentogingival fibers : Run from cementum to

gingiva.

Circular fibers : Hugs around the tooth.

Alveologingival group of fibers : Run from alveolar crest into lamina propria of free and attached gingiva.

Dentoperiosteal group : Run from cementum to periosteum of alveolar crest.

Functions : Braces marginal gingiva firmly against the tooth.

Withstand forces of mastication.

Unites attached gingiva with cementum to augment, action of junctional epithelium.

Age changes in oral mucosa Oral mucosa of an elderly patient has a smoother and dryer surface

than younger patient, due to dry therapy or any systemic diseases.

Epithelium appears thinner histologically.

Flattening of epithelial ridges.

Reduction in no. of filiform papillae.

Glossy and smooth appearance.

Langerhan’s cells become fewer with age, leading to decrease in cell mediated immunity.

Nodular varicose veins on the under surface of the tongue(caviar tongue).

Decrease in cellularity occurs in lamina propria with increase in collagen.

Sebaceous (Fordyce’s spots) glands of lips and cheeks increase with age.

Elderly post menopausal women, have symptoms such as dryness of mouth, burning sensations and abnormal taste.

Clinical Considerations

Classification of oral lesions :

Mucosal lesions : Leukoedema Oral leukoplakia Proliferative verrucous leukoplakia Epithelial dysplasia Oral hairy leukoplakia Oral lichen planus Candidiasis

Oral ulcerative lesions : Acute : Traumatic Bacterial Troponemal

Viral Fungal Drug reactions Erythema Multiforme Lupus Erythematosus Reiter’s syndrome

Chronic : Vesiculobullous lesions Malignant diseases

Recurrent : Recurrent Apthous stomatitis :

- Major Apthous ulcers

- Minor Apthous ulcers

Herpetiform ulcers Bechet’s syndrome

Acute ulcerative : Acute necrotizing ulcerative gingivostomatitis (ANUG) Streptococcal gingivostomatitis Oral Tuberculosis Gonococcal stomatitis

Syphilis :

- Congenital syphilis

- Primary syphilis

- Secondary syphilis

- Tertiary syphilis Fungal : Oral Candidiasis Histoplasmosis

Viral : Herpes simplex Recurrent Herpes simplex Herpes labialis

Varicella zoster Coxsackie

Discoid Lupus Erythematosus

Reiter’s syndrome Bechet’s syndrome

Drug Reactions : Barbiturates, Salicylates, Phenolphthalein, Quinine, digitalis, Grisefulvin, Dilantin

Chronic ulcerative : Pemphigus vulgaris Mucous membrane (cicatricial) pemphigoid Traumatic Granuloma

Hyperpigmentation of oral mucosa : Exogenous :

Foreign material – Amalgam tattoos, , carbon, seeds, leaves of various plants, tobacco

Pharmacologic agents: Minocycline, AZT, anti-malarials, amiodarone, OCP, doxorubicin

Heavy metal exposure: bismuth, mercury, silver, lead, tin, copper

Endogenous : Systemic : Addison’s disease, Peutz-Jeghers syndrome,

hemochromatosis Neoplasms: nevi, oral and labial melanotic macules, melanoma Reactive process: post-inflammatory hyperpigmentation

Others :- Acute Tonsilitis

- Carcinoma of Tongue

- Angular Chelitis

- Torus Palatinus

- Torus Mandibularis

- Cold Sores- Oro Pharynx Necrosis

- Salivary gland stone

- Oral Fibroma

- Lingual Cavernous Hemangioma

- Lingual Hemangioma

- Mass on base of Tongue

- Sialocele

- Oro Maxillary Fistula

- Lichenoid reaction Pigmentation :

Melanoplakia

White sponge nevus

Keratotic lesions :

- Hyperplastic

- Atrophic

Dyskeratotic lesions – eg. Dyskeratotic leukoplakia

Malignant tumors :

- Oral Squamous cell carcinoma

- Adenocarcinoma Dermatological lesions :

- Stevens-Johnsons syndrome

- Lichen Planus

- Discoid Lupus Erythematosus

Developmental disturbances of Oral mucosa:

Fordyce’s disease (Fordyce’s granules)

It is a developmental anomaly characterized by heterotrophic

collections of sebaceous glands at various sites in oral cavity.

Clinical features :

Small yellow spots.

They form large plaques.

Found frequently in a bilateral symmetrical pattern on the mucosa

of cheeks, opposite molars and also on the inner surface of lips.

FOR

DYC

E’S

GR

AN

ULE

S


Yellow small macular or papular structures on buccal mucosa. They are usually symptomless.

Occasionally they are found on tongue, gingiva, frenum and palate.

Besides oral cavity, they are also found in esophagus, female

genitalia, palms and soles, parotid gland, larynx and orbit.

Histological features :

Heterotrophic collections of sebaceous glands are common in skin,

but not associated with hair follicles.

Glands are usually superficial and may consist of only a few or

many lobules, grouping around one or more ducts opening on the

surface of mucosa.

Ducts may show keratin plugging.

HIS

TO

LOG

ICA

L IMA

GE

Lobules of Sebaceous glands emptying into ductal structures that communicate with the surface of the mucosa.

HIS

TO

LOG

ICA

L IMA

GE


Excessive accumulation of larger lobules of Sebaceous glands that often produce a noticeable mucosa swelling.

Focal Epithelial Hyperplasia (Heck’s disease)

Clinical features :

Primarily occurs in children.

It is HPV induced epithelial proliferation and is known to be

produced by subtypes of HPV, i.e. HPV -13 and possibly HPV –

32.

HEC

K’S

DIS

EA

SE Multiple Sessile and papillary lesions of the anterior gingiva and labial mucosa

of an adult.

No gender predilection.

Site – Labial, buccal, lingual mucosa. Some gingival and tonsillar

lesions have also been reported.

Fissured appearance of entire mucosal area, due to clustering of the

hyper plastic lesions.

Lesion is papillary in nature.

Histological appearance :

Focal acanthosis of oral epithelium.

Mucosa is 8-10 times thicker than normal.

Lesional rete ridges are at same depths as normal rete ridges.

Ridges are widened and club shaped.

Mitotic figures (mitosoid cell) seen.

Sessile in nature.

HIS

TO

LOG

ICA

L IMA

GE Spinous layer epithelial cells with unusual arrangement of the nuclear material

resembling abnormal mitotic figures (mitosoid cells).

Lacks central keratin filled core of keratoacanthoma.

Lacks sub epithelial foamy or granular histocytes like cells required

for diagnosis of Verruciform Xanthoma.

Leukoedema Common oral mucosa condition of unknown cause.

More common in blacks than in whites.

Clinical Features :

Diffuse, grayish- white, milky, opalescent appearance of mucosa.

Wrinkles present on the surface of mucosa.

Lesion does not rub off.

Occurs bilaterally but adjacent mucosa can also be involved.

Occurs mainly on buccal mucosa and extends up to labial mucosa.

Sometimes it can also involve floor of the mouth.


Increase in thickness of the epithelium.

Intracellular edema of the spinous layer is seen.

Pyknotic nuclei present in large vacuolated cells.

Epithelial surface is frequently parakeratinized

Rete ridges are broad and elongated.

HIS

TO

LOG

ICA

L IMA

GE

Developmental disturbances of Gingiva :

Fibromatosis gingivae :

Also called Elephantiasis gingivae, hereditary gingival

fibromatosis, congenital microgingivae.

It is a diffused fibrous overgrowth of gingival tissues.

It is considered Hereditary, being transferred from dominant

autosomal gene.

Clinical features :

It is a dense, diffuse, smooth or nodular overgrowth of gingival tissues usually appearing at the time of eruption of permanent incisors.


Epithelium thickened.

Elongated Rete pegs.

Coarse bundle of collagen fibers with few fibroblasts and blood

vessels.

Retrocuspid Papilla

Small, 2-4 mm slightly elevated nodule on the lingual mucosa of

mandibular cuspids.

Soft, well circumscribed, sessile, mucosal nodule, bilateral but can

also be unilateral.

Prominent in children.

CLIN

ICA

L IMA

GE A reddish, slightly-raised sessile small nodule behind or lingual to the lower

cuspid tooth.


Appears as an elevated mucosal tag often showing mild

hyperkeratosis or hyperparakeratosis.

Surfaced of orthokeratinized or parakeratinized squamous

epithelium.

Can be with or without acanthosis.

Underlying connective tissue is highly vascularised.

Large stellate fibroblasts.

Occasional epithelial rests.

Developmental disturbances of Tongue :

Aglossia and Microglossia syndrome

Very rare.

Associated with malformations in extremities, mainly hands and

feet, cleft palate.

Actually, Aglossia syndrome is a microglossia with extreme

glossoptosis (Rudimentary or small tongue).

Mandible does not grow in the anterior direction due to lack of muscular stimulus.

It’s etiology is unknown, but some say it’s some sort of fetal cell traumatism in first few weeks of gestation.

CLIN

ICA

L IMA

GE Congenital short lingual frenum of the tongue with microglossia

Macroglossia

Also called as tongue hypertrophy, prolapsus of tongue, enlarged

tongue, pseudomacroglossia.

It means large tongue.

May occur due to some congenital syndromes. E.g. Down’s

syndrome and Beckwith- wiedmann syndrome.

MA

CR

OG

LOS

SIA

Ankyloglossia or Tongue tie

Occurs when inferior frenum attaches to the bottom of the tongue

and resists it’s free movement.

Tongue tie may contribute to dental problems as well, causing

persistent gap between mandibular incisors

There is difficulty in speech and feeding.

Frenulectomy is recommended.

ANKYLOGLOSSIA IMAGES

Cleft tongue

A complete cleft or bifid tongue is a rare condition.

Occurs due to lack of merging of lateral lingual swellings.

A partial cleft tongue is more common and is actually a deep

groove in the midline of dorsal surface.

It occurs due to incomplete merging and faliure of groove

obliteration by underlying mesenchymal proliferation.

It is a feature of oral- facial- digital syndrome.

Scrotal tongue/ fissured tongue, lingua plicata

Grooves that vary in depth are present along the dorsal and lateral

aspects of tongue.

A polygenic mode of inheritance is suspected.

Seen in Melkersson – Rosenthal syndrome, Down’s syndrome,

Geographic tongue (Benign migratory glossitis)

Clinical images


Increase in the thickness of the lamina propria.

Loss of filiform papillae of surface mucosa.

Hyperplasia of rete pegs.

Mixed inflammatory infiltrate in lamina propria.

Median Rhomboid Glossitis

Post dorsal point of fusion is occasionally defective, leaving a

rhomboid shape, smooth and erythematous mucosa.

Lack of papillae/ taste buds.

Occurs in candidiasis and also

known as ‘Chronic Atrophic

Candidiasis’.

Clinical features :

Kissing lesion : Infected cases may also demonstrate a midline soft

palate erythema in the area of routine contact with the underlying

tongue involvement. This is commonly called kissing lesion.


Smooth or nodular surface covered by atrophic stratified squamous

epithelium.

Dilated capillaries.

Fungiform and filiform papillae not seen.

Chronic inflammatory cell infiltrate may be seen.

Extreme elongation of rete processes

Dyskeratosis.

Histological images

Benign migratory glossitis (Geographic tongue)

Psoriasiform mucositis of the dorsum of tongue.

It’s dominant characteristic is constantly changing pattern of

serpiginous white lines surrounding areas of smooth, depapillated

mucosa.

Clinical images


Thickened keratin layer with neutorphils.

Inflammatory cells often produce small micro abscesses, called

Monroe's abscesses in keratin and spinous layer.

Rete ridges are thin and elongated.

Chronic inflammatory cells seen in variable numbers within

stroma.

HIS

TO

LOG

ICA

L IMA

GE Hyperkeratotic epithelium

Hairy tongue Also known as Lingua nigra, lingua villosa, lingua villosa nigra,

black hairy tongue.

It is a condition of defective desquamation of filiform papillae.

It may appear brown, white, green, pink.

Clinical images

Etiology :-

Hypertrophy of filiform papillae on dorsal surface of the

tongue.

Occurs due to poor oral hygiene.

Tobacco use.

Coffee and tea drinking.


Elongated filiform papillae.

Mild hyperkeratosis.

Occasional inflammatory cells.

Lingual varices (lingual/ sublingual varicosities)

Varix is a dilated, tortuous vein.

Appear as red or purple shot like clusters of vessels on ventral

surface and lateral borders of tongue as well as in floor of mouth.

Also occur in upper and lower lip, buccal mucosa, buccal

commissure.

Clinical images

Lingual thyroid nodule It is an anamolous condition in which follicles of thyroid tissue are

found in the substance of the tongue.

CLIN

ICA

LIMA

GE

Histological appearance : Nodules exhibit colloid degeneration or goiter.

HIS

TO

LOG

ICA

L IMA

GE Lingual thyroid nodule

Developmental disturbances of oral lymphoid tissue

Reactive lymphoid aggregate (Reactive lymphoid hyperplasia)

Lingual tonsil, located on the posterior portion of the tongue frequently

becomes inflamed and enlarged.

It is bilateral .

Also is called ‘foliate papillitis’ due to foliate papillaes present in this

area.

They are firm, nodular, sub mucosal mass.

They are tender.

CLIN

ICA

L IMA

GE Reddish smooth-surfaced papules of the posterior lateral border of

the tongue in the foliate papilla area.

HIS

TO

LOG

ICA

L IMA

GE Superficial and deep perivascular and periadnexal lymphoid infiltrate.

Lymphoid hamartoma Also called angiofollicular lymph node hyperplasia, angiomatous

lymphoid, castleman tumor, follicular reticuloma giant benign

lymphoma, hamartoma of lymphatics, giant lymph node

hyperplasia)

Castleman’s disease is a rare disorder characterized by

noncancerous benign growth that may develop in the lymph node

tissue throughout the body.

Most often, occurring in chest, stomach and neck.

Abnormal enlargement of lymph nodes occur.

3 types of Castleman's disease :

a) Hyaline vascular type (90%) : These are non cancerous

overgrowths.

b) Plasma cell type : Associated with fever, weight loss, skin rash,

early destruction of R.B.C.

c) Multicentric / Generalized Castleman’s disease :

Abnormal large liver and spleen (hepatospleenomegaly).

Exact cause of castleman’s disease is not known.

Some researches say it’s because of increase in production of

interleukin- 6 (IL-6)

Interleukin – 6 is a substitute produced by structures within lymph

nodes.

Angiolymphoid hyperplasia with eosinophilia

Also called Epitheloid hemangioma, histocytoid hemangioma,

pseudopyogenic granuloma, papular angioplasia, inflammatory

angiomatous nodules.

Uncommon disorder.

Present with isolated or grouped plaques or nodules in skin of head

and neck.

Lesion is benign.

A distinct entity, ALHE is marked by proliferation of blood vessels

with distinctive large endothelial cells.


Papules around ear may suggest ALHE enlarged endothelial cells

with uniform ovoid nuclei and intracytoplasmic vacuoles.

HIS

TO

LOG

ICA

L IMA

GE Benign cutaneous vascular tumor largely composed of epithelioid vascular cells

with focal glomeruloid features.

Lymphoepithelial cyst

Develops within a benign lymphoid aggregate or accessory tonsil

of the oral or pharyngeal mucosa.

Surface of such aggregates may be indented with tonsillar crypts.

The crypts may become obstructed by keratin or other debris.

Certain cases develop complete disunion of the crypt epithelium

from the surface epithelium.

HIS

TO

LOG

ICA

L IMA

GE Yellow lymphoepithelial cyst on the margin of the tongue


Lined by atrophic and often degenerated stratified squamous

epithelium.

Lack rete processes.

Minimal granular cell layer.

Rarely, mucus filled goblet cells may be seen within superficial

layers of the epithelium.

Orthokeratin seen sloughing from the epithelial surface into the

cystic lumen.

HIS

TO

LOG

ICA

L IMA

GE Often lined by squamous epithelium

HIS

TO

LOG

ICA

L IMA

GE Lined by non-neoplastic glandular epithelium

OR

AL LE

UKO

PLA

KIA

OR

AL V

ER

RU

CO

US

LE

UKO

PLA

KIA

EPIT

HELIA

L DYS

PLA

SIA Nodular leukoplakia showing severe epithelial dysplasia

OR

AL H

AIR

Y LE

UKO

PLA

KIA Leathery white callus on the side of the tongue

OR

AL H

AIR

Y LE

UKO

PLA

KIA It is considered pathognomonic for aids. When a clinician encounters a patient

with hairy leukoplakia, he assumes he is dealing with a person with HIV virus and recommends that the patient have serological test for HIV

OR

AL LIC

HEN

PLA

NU

S

CA

ND

IDIA

SIS

OR

AL U

LCER

ATIV

E LE

SIO

N

Acute Necrotizing Ulcerative Gingvostomatitis

OR

AL T

UB

ER

CU

LOS

IS

SYPH

ILIS

HIS

TO

PLA

SM

OS

IS

HER

PES

LAB

IALIS

CO

XS

AC

KIE

VIR

US

INFE

CTIO

N

DIS

CO

ID LU

PU

S

ERYTH

EM

ATO

SU

S (A.) Extraoral photograph of patient with discoid lupus erythematosus. Note the butterfly shaped rash on the malar area. (B) Intraoral photograph of the same patient showing erosive lesions surrounded by radiating white striae on the left buccal mucosa.

http://screening.iarc.fr/atlasoralglossdef.php?key=discoid%20lupus%20erythematosus&img

REIT

ER

’S S

YN

DR

OM

E Tongue lesion

BEC

HET’S

SYN

DR

OM

E

PEM

PH

GU

S V

ULG

AR

IS

MU

CO

US M

EM

BR

AN

E P

EM

PH

IGO

ID

REC

UR

REN

T A

PTH

OU

S

STO

MATIT

IS

Acute tonsllitis

TO

RU

S PA

LATIN

US

TO

RU

S M

AN

DIB

ULA

RIS

AN

GU

LAR

CH

ELIT

IS

CO

LD S

OR

ES

STEV

EN

S-JO

HN

SO

N S

YN

DR

OM

E Also called erythema multiforme

OR

AL P

HA

RYN

X N

EC

RO

SIS

Salivary gland stone

OR

AL FIB

RO

MA

LING

UA

L CAV

ER

NO

US

H

EM

AN

GIO

MA

MA

SS

AT B

AS

E O

F TH

E T

ON

GU

E

SIA

LOC

ELE

OR

AL M

AX

ILLARY FIS

TU

LA

References :

Tencate’s textbook of dental histology; 7th edition.

Orban’s textbook of oral histology; 11th edition.

Oral anatomy, histology& embryology ; berkovitz ; 3rd

edition.

Textbook of periodontology; Carranza ; 10th edition

Oral and Maxillofacial Pathology; Neville; 2nd edition.

Shafer’s Textbook of Oral Pathology; 6th edition.

Contemporary Oral and Maxillofacial Pathology ; 2nd

edition.

Handbook Of Oral Disease, diagnosis and

management ; Crispian scully ; 1st edition.

Francis.V.Howell. Oral mucous membrane lesions.

California Medicine 1964 ; 100(3); 186-91. Francis B. Quinn ,Matthew W. Ryan. Ulcerative

Lesions Of The Oral Cavity. UTMB Grand rounds 2002 ;1-11

Brad W. Neville, Terry A. Day. Oral Cancer and Precancerous Lesions. CA Cancer J Clin 2002;52:195-215

Oral Mucous Membrane

Documents

Transcript of Oral Mucous Membrane