MC CUNE –ALBRIGHT SYNDROMEpolyostotic fibrous dysplasia

Association of polyostotic fibrous dysplasia, precocious puberty, café-au-lait spots and other endocrinopathies due to hyperactivity of various endocrine glands.

HISTORY weil -- 1922. Donovan james Mc cune and Fuller albright

1937

ETIOLOGY Post zygotic mutation ----GS alpha gene

G protein -present in many cells, -involved in endocrine cell growth

and secretion - mutation –uncontrolled cell

function and increased harmonal secretion.

CLINICAL FEATURES Café-au-lait spots : (coffee with milk) increased amounts of melanin in basal

cells of epidermis . generally seen in lower lumbar spine,

sacrum, buttocks,upper back,neck,shoulder, lips, oral mucosa.

well defined unilateral macules –coast line of maine.

Respect midline.

Café-au-lait skin pigmentation. A) "coast of Maine" borders, and the tendency for the lesions to respect the midline

B) Typical lesions that are often found on the nape of the neck and the buttocks are shown (arrows).

Polyostotic fibrous dysplasia:-- More then 75% of the skeleton---

McCune Albright syndrome. (when few bones are involved--- JAFFE- LICHTENSTEIN SYNDROME.)

The fibrous growth in bones--- bony deformities and fractures.

facial assymetry of skull and jaw bones.

HOCKEY STICK DEFORMITY– leg length discripency due to the involvment of upper portion of femer.

ENDOCRINOPATHIES Mutation in g protein cause– uncontrolled

harmonal secretions in various endocrine glands.

Precocious puberty:-- In women ovarian cysts--- excess oestrogen

production causing 1.early menstrual bleeding –2 years

2.early development of breasts 3. irregular menstrual bleeding. In men early development of testis and pubic

hair

Thyroid gland:-- adenoma and goiter – causing

hyperthyroidism. Moderately elevated basal metabolic rate

Pituitary gland:-- somatotroph adenomas cause increased

growth harmone secretion causing acromegaly.

Adrenal gland:-- bilateral non pigmented adrenocortical

hyperplasia causes cushings syndrome.

Hypophosphotemia:-- Due to excess phosphate excretion from

urine causing rickets.

ORAL MANIFESTATIONS Enlarged , expanded and distorted jaws. Obliteration of maxillary sinus Oral pigmentation on the lips and buccal

mucosa. premature eruption of teeth.

RADIOGRAPHIC FINDINGS Roentgenographic examination lesion may be radiolucent , radiopaque or mixed. Radiopacity common in maxilla. Radiolucent area common in mandible and long

bones. Ground glass appearance:-- due to numerous ,

abnormal irregularly arranged bony trabaculae. Expansion of bone with thinned outer cortex

–classic feature. lion face (leontiasis ossea) Bone scanning:-: Asymptomatic sites of fibrous

dysplasia detection.

Reconstructed three-dimensional CT image shows lion face appearance due to asymmetrical involvement and enlargement of the bones of the face and the skull.

Plain X-ray films revealed increased density of the cranium, pelvic girdles and extremities.

LABORATORY DIAGNOSIS Precocious puberty : gonadotrophin

independent elevation of estrogen levels elevated liver enzymes or

hyperbilirubinemia. Due to mutation in G protien of hepatocytes

hypophosphatemia may result from increased urinary phosphate excretion.

Elevated thyroxine levels Serum growth hormone (GH) and

insulinlike growth factor-1 (IGF-1) levels elevated.

MALIGNANCIES ASSOCIATED WITH ALBRIGHT SYNDROME OSTEOSARCO MC CUNE ALBRIGHT

SYNDROME(most common) CHONDROSARCO MC CUNE ALBRIGHT

SYNDROME FIBROSARCO MC CUNE ALBRIGHT SYNDROME LIPOSARCO MC CUNE ALBRIGHT SYNDROME THYROID MALIGNANCIES.

HISTOLOGICAL FINDINGS Histology:-- areas of fibrous metaplasia, Lesions typically expand concentrically from

the medullary cavity outward not capsulated Irregular trabacular pattern resembling

CHINESE LETTER PATTERN

DIFFERENTIAL DIAGNOSIS Gigantism and Acromegaly

Glucocorticoid Therapy and Cushing SyndromeHyperthyroidismHypophosphatemic RicketsNeurofibromatosis

TREATMENT Only symptomatic with multi disciplinary approach Bone treatments

Surgical bone grafting Ovary surgery

Surgical ovary cyst removal Estrogen inhibitors

Testolactone (blocks estrogen synthesis) Thyroid-inhibiting medications --Propylthiouracil. Treatments for phosphorus problems(low levels of phosphorus in

the blood due to excessive losses of phosphate in the urine. This may cause bone weakening and the condition called rickets ) --Oral phosphates Vitamin D

growth harmone:-Therapy has included surgical removal of the area of the pituitary which is secreting the hormone, and the use of new, synthetic analogs of the hormone somatostatin, which suppress growth hormone secretion.