World Health Organization Classification of Tumours

Pathology & Genetics Head and Neck Tumours

IARC

WHO Classification Head and Neck Tumours

Edited by Leon Barnes, John W. Eveson, Peter Reichart, David Sidransky

World Health Organization Classification of TumoursKleihues P ., Cavenee W.K. (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Nervous System. IARC Press: Lyon 2000 ISBN 92 83 22409 4 Hamilton S.R., Aaltonen L.A. (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Digestive System. IARC Press: Lyon 2000 ISBN 92 83 22410 8 Jaffe E.S., Harris N.L., Stein H., Vardiman J.V. (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Haematopoietic and Lymphoid Tissues. IARC Press: Lyon 2001 ISBN 92 83 22411 6

Fletcher C.D., Unni K.K., Mertens F . (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Soft Tissue and Bone. IARC Press: Lyon 2002 ISBN 92 832 2413 2

Tavassoli F .A., Devilee P . (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Breast and Female Genital Organs IARC Press: Lyon 2003 ISBN 92 832 2412 4

Eble J.N., Sauter G., Epstein J.E., Sesterhenn I.A. (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Urinary System and Male Genital Organs. IARC Press: Lyon 2004 ISBN 92 832 2415 9 Barnes L., Eveson J.W., Reichart P ., Sidransky D. (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Head and Neck Tumours. IARC Press: Lyon 2005 ISBN 92 832 2417 5

Travis W.D., Brambilla E., MllerHermelink H.K., Harris C.C. (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Lung, Pleura, Thymus and Heart. IARC Press: Lyon 2004 ISBN 92 832 2418 3

DeLellis R.A., Lloyd R.V., Heitz, P .U., Eng C. (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Endocrine Organs. IARC Press: Lyon 2004 ISBN 92 832 2416 7

This book and all other volumes of the series can be purchased from:World Health Organization (WHO) WHO Press 1211 Geneva 27 (Switzerland) Tel. +41 22 791 3264 Fax +41 22 791 4857 bookorders@who.int online: http://www.who.int/bookorders WHO Publications Center Albany, NY 12210 (USA) Tel. (518) 436 9686 Fax (518) 436 7433 qcorp@compuserve.com

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World Health Organization Classification of TumoursWHO OMS

International Agency for Research on Cancer (IARC)

Pathology and Genetics of Head and Neck TumoursEdited by

Leon Barnes John W. Eveson Peter Reichart David Sidransky

IARCPress Lyon, 2005

World Health Organization Classification of TumoursSeries Editors Paul Kleihues, M.D. Leslie H. Sobin, M.D.

Pathology and Genetics of Head and Neck TumoursEditors Leon Barnes, M.D. John W. Eveson, M.D. Peter Reichart, M.D. David Sidransky, M.D. Wojciech Biernat, M.D. Vanessa Meister Marlen Grassinger Stephan Rappo Sibylle Sring Nobert Wey Thomas Odin Team Rush 69603 Villeurbanne, France IARCPress International Agency for Research on Cancer (IARC) 69008 Lyon, France

Coordinating Editor Layout

Illustrations

Printed by

Publisher

This volume was produced in collaboration with the

International Academy of Pathology (IAP)and the

Department of Pathology, University Hospital, Zurich, Switzerland

The WHO Classification of Head and Neck Tumours presented in this book reflects the views of a Working Group that convened for an Editorial and Consensus Conference in Lyon, France, July 16-19, 2003.Members of the Working Group are indicated in the List of Contributors on page 371.

Contents1 Nasal cavity and paranasal sinusesWHO and TNM classification Introduction Malignant epithelial tumours Squamous cell carcinoma Lymphoepithelial carcinoma Sinonasal undifferentiated carcinoma Adenocarcinoma Salivary gland-type carcinomas Neuroendocrine tumours Benign epithelial tumours Schneiderian papillomas Respiratory epithelial adenomatoid hamartoma Salivary gland-type adenomas Soft tissue tumours Malignant soft tissue tumours Borderline and LMP tumours Benign soft tissue tumours Tumours of bone and cartilage Malignant tumours Benign tumours Haematolymphoid tumours Neuroectodermal tumours Germ cell tumours Secondary tumours

910 12 15 18 19 20 24 26 28 33 34 35 43 46 51 53 58 65 76 80

Epithelial precursor lesions Benign epithelial tumours Papilloma / papillomatosis Benign salivary gland-type tumours Malignant soft tissue tumours Inflammatory myofibroblastic tumour Benign soft tissue tumours Haematolymphoid tumours Tumours of bone and cartilage Mucosal malignant melanoma Secondary tumours

140 144 146 147 150 152 155 156 160 162

4 Oral cavity and oropharynxWHO and TNM classification Introduction Malignant epithelial tumours Squamous cell carcinoma Lymphoepithelial carcinoma Epithelial precursor lesions Proliferative verrucous leukoplakia Precancerous conditions Benign epithelial tumours Papillomas Granular cell tumour Keratoacanthoma Papillary hyperplasia Median rhomboid glossitis Salivary gland tumours Kaposi sarcoma Lymphangioma Ectomesenchymal chondromyxoid tumour Focal oral mucinosis Congenital granular cell epulis Haematolymphoid tumours Malignant melanoma Secondary tumours

163164 166 168 176 177 180 180 182 185 187 189 189 190 193 195 196 197 198 199 206 208

2 NasopharynxWHO and TNM classification Introduction Malignant epithelial tumours Nasopharyngeal carcinoma Papillary adenocarcinoma Salivary gland-type carcinomas Benign epithelial tumours Nasopharyngeal angiofibroma Haematolymphoid tumours Tumours of bone and cartilage Secondary tumours

8182 83 85 98 98 99 102 104 106 106

5 Salivary glandsWHO and TNM classification Introduction Malignant epithelial tumours Acinic cell carcinoma Mucoepidermoid carcinoma Adenoid cyctic carcinoma Polymorphous low-grade adenocarcinoma Epithelial-myoepithelial carcinoma Clear cell carcinoma, N.O.S. Basal cell adenocarcinoma Malignant sebaceous tumours Cystadenocarcinoma Low-grade cribriform cystadenocarcinoma Mucinous adenocarcinoma Oncocytic carcinoma Salivary duct carcinoma

209210 212 216 219 221 223 225 227 229 231 232 233 234 235 236

3 Hypopharynx, larynx and tracheaWHO and TNM classification Introduction Malignant epithelial tumours Squamous cell carcinoma Verrucous carcinoma Basaloid squamous cell carcinoma Papillary squamous cell carcinoma Spindle cell carcinoma Acantholytic squamous cell carcinoma Adenosquamous carcinoma Lymphoepithelial carcinoma Giant cell carcinoma Malignant salivary gland-type tumours Neuroendocrine tumours

107108 111 118 122 124 126 127 129 130 132 133 134 135

Adenocarcinoma, N.O.S. Myoepithelial carcinoma Carcinoma ex pleomorphic adenoma Carcinosarcoma Metastasizing pleomorphic adenoma Squamous cell carcinoma Small cell carcinoma Large cell carcinoma Lymphoepithelial carcinoma Sialoblastoma Benign epithelial tumours Pleomorphic adenoma Myoepithelioma Basal cell adenoma Warthin tumour Oncocytoma Canalicular adenoma Sebaceous adenoma Lymphadenomas Ductal papillomas Cystadenoma Soft tissue tumours Haemangioma Haematolymphoid tumours Secondary tumours

238 240 242 244 245 245 247 249 251 253 254 259 261 263 266 267 268 269 270 273 275 276 277 281

Bone related lesions Ossifying fibroma Fibrous dysplasia Osseous dysplasias Central giant cell lesion Cherubism Aneurysmal bone cyst Simple bone cyst

319 321 323 324 325 326 327

7 EarWHO classification External ear Tumours of ceruminous glands Cylindroma Squamous cell carcinoma Embryonal rhabdomyosarcoma Fibrous dysplasia Osteoma and exostosis Angiolymphoid hyperplasia with eosinophilia Kimura disease Idiopathic pseudocystic chondromalacia Chondrodermatits nodularis chronica helicis Middle ear Cholesterol granuloma and cholesteatoma Adenoma Papillary tumours Choristoma Squamous cell carcinoma Meningioma Inner ear Vesticular schwannoma Neurofibromatosis type 2 Lipoma of the internal auditory canal Haemangioma Endolymphatic sac tumour Haematolymphoid tumours Langerhans cell histiocytosis Secondary tumours

329330 331 332 334 335 336 337 338 340 341 341 342 345 346 348 349 350 351 353 354 354 355 357 358 360

6 Odontogenic tumours

283

WHO classification 284 Introduction 285 Odontogenic carcinomas 287 Ameloblastic carcinomas 287 Primary intraosseous squamous cell carcinomas 290 Clear cell odontogenic carcinoma 292 Ghost cell odontogenic carcinoma 293 Odontogenic sarcomas 294 Benign tumours Odontogenic epithelium with mature fibrous stroma, without odontogenic ectomesenchyme Ameloblastomas 296 Squamous odontogenic tumour 301 Calcifying epithelial odontogenic tumour 302 Adenomatoid odontogenic tumour 304 Keratocystic odontogenic tumour 306 Odontogenic epithelium with odontogenic ectomesenchyme, with or without tissue formation Ameloblastic fibroma / fibrodentinoma 308 Ameloblastic fibro-odontoma 309 Odontoma, complex type 310 Odontoma, compound type 311 Odontoameloblastoma 312 Calcifying cystic odontogenic tumour 313 Dentinogenic ghost cell tumour 314 Mesenchyme and/or odontogenic ectomesenchyme, with or without odontogenic epithelium Odontogenic fibroma 315 Odontogenic myxoma / myxofibroma 316 Cementoblastoma 318

8 Paraganglionic systemIntroduction Carotid body paraganglioma Jugulotympanic paraganglioma Vagal paraganglioma Laryngeal paraganglioma

361362 364 366 368 370

Contributors Source of charts and photographs References Subject index

371 376 378 422

CHAPTER 1Tumours of the Nasal Cavity and Paranasal Sinuses

Although the nasal cavity and paranasal sinuses occupy a relatively small anatomical space, they are the site of origin of some of the more complex, histologically diverse group of tumours in the entire human body. These include neoplasms derived from mucosal epithelium, seromucinous glands, soft tissues, bone, cartilage, neural/neuroectodermal tissue, haematolymphoid cells and the odontogenic apparatus. Many of the tumours are similar to those found elsewhere in the body but a few, such as the olfactory neuroblastoma, are unique to this site.

WHO histological classification of tumours of the nasal cavity and paranasal sinusesMalignant epithelial tumours Squamous cell carcinoma Verrucous carcinoma Papillary squamous cell carcinoma Basaloid squamous cell carcinoma Spindle cell carcinoma Adenosquamous carcinoma Acantholytic squamous cell carcinoma Lymphoepithelial carcinoma Sinonasal undifferentiated carcinoma Adenocarcinoma Intestinal-type adenocarcinoma Non-intestinal-type adenocarcinoma Salivary gland-type carcinomas Adenoid cystic carcinoma Acinic cell carcinoma Mucoepidermoid carcinoma Epithelial-myoepithelial carcinoma Clear cell carcinoma N.O.S. Myoepithelial carcinoma Carcinoma ex pleomorphic adenoma Polymorphous low-grade adenocarcinoma Neuroendocrine tumours Typical carcinoid Atypical carcinoid Small cell carcinoma, neuroendocrine type Benign epithelial tumours Sinonasal papillomas lnverted papilloma (Schneiderian papilloma, inverted type) Oncocytic papilloma (Schneiderian papilloma, oncocytic type) Exophytic papilloma (Schneiderian papilloma, exophytic type) Salivary gland-type adenomas Pleomorphic adenoma Myoepithelioma Oncocytoma Soft tissue tumours Malignant tumours Fibrosarcoma Malignant fibrous histiocytoma Leiomyosarcoma Rhabdomyosarcoma Angiosarcoma Malignant peripheral nerve sheath tumour Borderline and low malignant potential tumours Desmoid-type fibromatosis Inflammatory myofibroblastic tumour Glomangiopericytoma (Sinonasal-type haemangiopericytoma) Extrapleural solitary fibrous tumour 8070/3 8051/3 8052/3 8083/3 8074/3 8560/3 8075/3 8082/3 8020/3 8144/3 8140/3 8200/3 8550/3 8430/3 8562/3 8310/3 8982/3 8941/3 8525/3 8240/3 8249/3 8041/3 Benign tumours Myxoma Leiomyoma Haemangioma Schwannoma Neurofibroma Meningioma Tumours of bone and cartilage Malignant tumours Chondrosarcoma Mesenchymal chondrosarcoma Osteosarcoma Chordoma Benign tumours Giant cell lesion Giant cell tumour Chondroma Osteoma Chondroblastoma Chondromyxoid fibroma Osteochondroma (exostosis) Osteoid osteoma Osteoblastoma Ameloblastoma Nasal chondromesenchymal hamartoma Haematolymphoid tumours Extranodal NK/T cell lymphoma Diffuse large B-cell lymphoma Extramedullary plasmacytoma Extramedullary myeloid sarcoma Histiocytic sarcoma Langerhans cell histiocytosis Neuroectodermal Ewing sarcoma Primitive neuroectodermal tumour Olfactory neuroblastoma Melanotic neuroectodermal tumour of infancy Mucosal malignant melanoma Germ cell tumours Immature teratoma Teratoma with malignant transformation Sinonasal yolk sac tumour (endodermal sinus tumour) Sinonasal teratocarcinosarcoma Mature teratoma Dermoid cyst Secondary tumours 8840/0 8890/0 9120/0 9560/0 9540/0 9530/0

9220/3 9240/3 9180/3 9370/3

9250/1 9220/0 9180/0 9230/0 9241/0 9210/0 9191/0 9200/0 9310/0

8121/1 8121/1 8121/0 8940/0 8982/0 8290/0

9719/3 9680/3 9734/3 9930/3 9755/3 9751/1

9260/3 9364/3 9522/3 9363/0 8720/3

8810/3 8830/3 8890/3 8900/3 9120/3 9540/3 8821/1 8825/1 9150/1 8815/1

9080/3 9084/3 9071/3 9080/0 9084/0

__________ 1 Morphology code of the International Classification of Diseases for Oncology (ICD-O) {821} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded /0 for benign tumours, /3 for malignant tumours, and /1 for borderline or uncertain behaviour.

10

Tumours of the nasal cavity and paranasal sinuses

TNM classification of carcinomas of the nasal cavity and paranasal sinusesTNM classification 1,2 TNM classification of carcinomas of the nasal cavity and sinuses # T Primary tumour TX Primary tumour cannot be assessed T0 No evidence of primary tumour Tis Carcinoma in situ Maxillary sinus T1 Tumour limited to the antral mucosa with no erosion or destruction of bone T2 Tumour causing bone erosion or destruction, including extension into hard palate and/or middle nasal meatus, except extension to posterior antral wall of maxillary sinus and pterygoid plates T3 Tumour invades any of the following: bone of posterior wall of maxillary sinus, subcutaneous tissues, floor or medial wall of orbit, pterygoid fossa, ethmoid sinuses T4a Tumour invades any of the following: anterior orbital contents, skin of cheek, pterygoid plates, infratemporal fossa, cribriform plate, sphenoid or frontal sinuses T4b Tumour invades any of the following: orbital apex, dura, brain, middle cranial fossa, cranial nerves other than maxillary division of trigeminal nerve V2, nasopharynx, clivus Nasal cavity and ethmoid sinus T1 Tumour restricted to one subsite of nasal cavity or ethmoid sinus, with or without bony invasion T2 Tumour involves two subsites in a single site or extends to involve an adjacent site within the nasoethmoidal complex, with or without bony invasion T3 Tumour extends to invade the medial wall or floor of the orbit, maxillary sinus, palate, or cribriform plate T4a Tumour invades any of the following: anterior orbital contents, skin of nose or cheek, minimal extension to anterior cranial fossa, pterygoid plates, sphenoid or frontal sinuses T4b Tumour invades any of the following: orbital apex, dura, brain, middle cranial fossa, cranial nerves other than V2, nasopharynx, clivus N Regional lymph nodes 3 NX Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis N1 Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension N2 Metastasis as specified in N2a, 2b, 2c below N2a Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension N2b Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension N2c Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension N3 Metastasis in a lymph node more than 6 cm in greatest dimension Note: Midline nodes are considered ipsilateral nodes. M Distant metastasis MX Distant metastasis cannot be assessed M0 No distant metastasis M1 Distant metastasis Stage grouping Stage 0 Tis Stage I T1 Stage II T2 Stage III T1, T2 T3 Stage IVA T1, T2, T3 T4a Stage IVB T4b Any T Stage IVC Any T

N0 N0 N0 N1 N0, N1 N2 N0, N1, N2 Any N N3 Any N

M0 M0 M0 M0 M0 M0 M0 M0 M0 M1

__________ 1 {947,2418}. 2 A help desk for specific questions about the TNM classification is available at www.uicc.org/index.php?id=508 . 3 The regional lymph nodes are the cervical nodes

WHO and TNM classification

11

Tumours of the nasal cavity and paranasal sinuses: Introduction

L. Barnes L.L.Y. Tse J.L. Hunt

M. Brandwein-Gensler H.D. Curtin P. Boffetta

AnatomyThe nasal cavities are separated in the midline by the nasal septum. Each cavity is wide caudally, and narrow cranially. The roof of the nasal cavity is formed by the thin (0.5 mm) cribriform plate. The floor is the hard palate, formed by the palatine processes of the maxillae and the horizontal portions of the palatine bones. The lateral nasal wall contains the maxillary and ethmoid ostia, plus three or four turbinates. These turbinates are delicate scroll-like projections of bone and vascular soft tissue that become smaller as they ascend in the nasal cavity. They attach to the lateral nasal wall anteriorly, and have a free edge posteriorly. The turbinates are covered with a thick mucous membrane and contain a dense, thick-walled venous plexus. The upper margins of the nasal fossa are bound laterally by the superior nasal turbinate and adjacent lateral nasal wall, and medially by the nasal septum. This region is the olfactory recess and it has a yellowish epithelium, the olfactory mucosa (OM). This mucosa contains bipolar olfactory nerve fibers that cross through the cribriform plate. The terminal axons of the olfactory nerves extend to the free surface of the epithelium, where they expand into knob-like protrusions bearing cilia (olfactory cilia). Bowmans glands, or olfactory glands, within the lamina propria appear similar to serous minor salivary glands. The nasal cavity and paranasal sinuses are lined by Schneiderian mucosa, consisting of pseudostratified columnar ciliated epithelium with interspersed goblet cells. The lamina propria within the paranasal sinuses, especially the maxillary antrum, is loose and well vascularized, with seromucinous glands, and can easily become polypoid as a result of edema. The goblet cell component of the mucosal surface and seromucinous glands is variable. In chronic sinusitis, goblet cell hyperplasia can result in a papillary mucosal lesion. The major portion of the nasal septum is

formed by the perpendicular plate of the ethmoid bone posteriorly and the septal cartilage anteriorly. The vomer completes the posteroinferior portion of the septum. The septum is lined by relatively thin, ciliated respiratory mucosa, which may regularly undergo squamous metaplasia. The underlying thin lamina propria, although containing seromucinous glands, is tethered to the septal cartilage, restricting reactive polyp formation. The frontal sinus These paired sinuses reside between the internal and external cranial tables and drain either via a nasofrontal duct into the frontal recess or more directly into the anterior infundibulum, or less often, into the anterior ethmoid cells, which in turn will open into the infundibulum of the bulla ethmoidalis. Ethmoid complex This paired complex of sinuses contains 3-18 cells that are grouped as anterior, middle, or posterior, according to the location of their ostia. There is an inverse relationship between the number and size of the cells. Generally, the posterior cells are both larger and fewer than the anterior cells. Each ethmoid labyrinth lies between the orbit and the upper nasal fossa. The left and right groups of ethmoid cells are connected in the midline by the cribriform plate (nasal roof) of the ethmoid bone. The cribriform plate is an important landmark in evaluation of

sinonasal tumour stage - violation of the cribriform plate signifies direct extension of the tumour into the anterior cranial fossa. The crista galli is a distinctive pointed bony landmark that extends from the midline of the cribriform plate upward into the floor of the anterior cranial fossa. The perpendicular plate of the ethmoid bone extends downward from the cribriform plate to contribute to the nasal septum. The medial wall of each ethmoid labyrinth is formed by a thin lamella of bone from which arise the middle, superior, and supreme turbinates. The lateral ethmoid wall is formed by the thin lamina papyracea, which separates the ethmoid cells from the orbit. This is yet another important landmark for tumour staging. Tumour violation of the lamina papyracea may necessitate including the orbit and globe with the surgical resection. This area should be sampled in a maxillectomy specimen a) if the globe has not been removed (as the lamina papyracea represents the lateral orbital margin), or b) if orbital exenteration has been performed. The roof of the ethmoid complex is formed by a medial extension of the orbital plate of the frontal bone, which projects to articulate with the cribriform plate. This is often referred to as the fovea ethmoidalis. Sphenoid sinus The average adult sphenoid sinus measures 20 mm high, 23 mm long, and 17 mm wide. The relationship of the posterior extension of the sphenoid in relation to the sella turcica is variable. The sphenoid sinus septum is usually in the midline, and anteriorly aligned with the nasal septum. However, it can also deviate far to one side creating two unequal sinus cavities. With the exception of the sinus roof, the other sinus walls are of variable thickness depending on the degree of pneumatization. The sphenoid roof is thin, often measuring only 1 mm. (planum sphenoidale), and is vulnerable to perforation during surgery. The sinus roof relates to the floor of the anterior cranial fossa, anteriorly; the optic chiasm and

Fig. 1.1 Normal coronal T1 WI shows foramen rotundum (white arrow) and entrance to the Vidian canal (black arrow).

12

Tumours of the nasal cavity and paranasal sinuses

the sella turcica, posteriorly. The lateral sphenoid wall is related to the orbital apex, the optic canal, the optic nerve, and the cavernous sinus, containing the internal carotid artery. The sinus floor is the roof of the nasopharynx, and the anterior sinus wall is the back of the nasal fossa. Maxillary sinus The maxillary sinus lies within the body of the maxillary bone. Behind the orbital rims, each sinus roof/orbital floor slants obliquely upward so that the highest point of the sinus is in the posteromedial portion, lying directly beneath the orbital apex. The medial antral wall is the inferior lateral wall of the nasal cavity (party wall). The curved posterolateral wall separates the sinus from the infratemporal fossa. The anterior sinus wall is the facial surface of the maxilla that is perforated by the infraorbital foramen below the orbital rim. The floor of the sinus is lowest near the second premolar and first molar teeth and usually lies 3-5 mm below the nasal floor. The lower expansion of the antrum is intimately related to dentition. The location of the maxillary sinus ostia, is high on the medial wall. They drain through the ethmoidal infundibulum and then the nasal fossa. This pattern of drainage in the erect position is accomplished by intact ciliary action. The maxillary hiatus is a bony window leading to the interior of the maxillary sinus. The hiatus is normally partially covered by portions of four bones: the perpendicular plate of the palatine bone, posteriorly; the lacrimal bone, anterosuperiorly; the inferior turbinate, inferiorly, and above the turbinate attachment, the uncinate process of the ethmoid bone.

Fig. 1.2 Malignancy of ethmoid and nasal cavity. Coronal CT with contrast. The tumour erodes the cribriform plate and fovea ethmoidalis (white arrowhead). The lamina papyracea is eroded (black arrowhead) but the fat (white arrow) medial to the medial rectus (MR) is normal. The orbital fat is not invaded. The margin (black arrow) of the tumour in the maxillary sinus is separable from the obstructed secretions because of different densities.

Fig. 1.3 Malignancy of upper nasal cavity invading orbital fat and extending intracranially. The tumour (white arrow) extends through the roof of the ethmoid and along the roof of the orbit (white arrowhead). The tumour bulges (black arrow) the periorbita near the medial rectus but breaks through into the orbital fat more superiorly (black arrowhead). Note that the tumour enhances intermediately and less intensely than the mucosa.

sinuses {2378}. Malignant neoplasms of this region may lead to significant morbidity and disfigurement. The incidence of cancer of the nasal cavity and paranasal sinuses (sinonasal cancer) is low in most populations (5 cm), bone invasion, profound nuclear pleomorphism, increased mitotic activity (>4/10 high power fields), necrosis, and proliferation index >10% {216,343,1364, 2600}.

C

D

Fig. 1.52 Glomangiopericytoma. A A characteristic histomorphologic feature is the presence of prominent perivascular hyalinization. B Tumour cells are ovoid or polygonal. Note the delicate interspersed vascular spaces. C Streaming short spindly cells. Vascular spaces may not be obvious. D Immunostaining for muscle-specific actin is mainly in vessels and focally in tumour cells.

Synonyms Sinonasal haemangiopericytoma; haemangiopericytoma-like tumour, sinonasal glomus tumour; haemangiopericytoma. Epidemiology Sinonasal glomangiopericytomas predilect to the nasal cavity and paranasal sinuses, where they comprise