Sinonasal undifferentiated carcinoma

Nasal cavity, paranasal sinuses, nasopharynx

Sinonasal carcinoma

Authors: Rifat Mannan, M.D., Songyang Yuan, M.D., Ph.D.

Topic Completed: 1 December 2013

Minor changes: 28 December 2020

Copyright: 2004-2021, PathologyOutlines.com, Inc.

PubMed Search: Undifferentiated anaplastic carcinoma sinonasal[TI]

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Table of Contents

Cite this page: Mannan R, Yuan S. Sinonasal undifferentiated carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/nasalsnuc.html. Accessed January 22nd, 2021.

Definition / general

Rare, highly aggressive and clinicopathologically distinct malignancy of uncertain histogenesis

Terminology

Sinonasal undifferentiated carcinoma (SNUC)
Undifferentiated (anaplastic) carcinoma

Epidemiology

Rare tumor, 85% smokers
More common in men, occurs over a wide age range
Median presentation in the sixth decade (Adv Anat Pathol 1999;6:317)

Sites

Nasal cavity, maxillary antrum and ethmoid sinus are typically involved, either alone or in combination
Usually presents as an extensively infiltrative disease involving multiple sites, including nasal cavity, one or more paranasal sinuses, orbit, skull base and brain

Etiology

No known etiologic agents
Typically negative for Epstein-Barr virus but there are reports of EBV RNA positivity in Asian (Am J Surg Pathol 1994;18:391) and Italian patients (Otolaryngol Head Neck Surg 1995;112:659) with SNUC
Some cases have been reported to develop following radiation therapy for nasopharyngeal carcinoma (Am J Surg Pathol 2002;26:371)

Clinical features

Patients typically present with multiple symptoms such as nasal obstruction, epistaxis, proptosis, visual disturbances, facial pain and symptoms of cranial nerve involvement
Symptoms usually develop over a relatively short duration (weeks to months)
This is a characteristic, though not pathognomonic feature of SNUC

Radiology images

Images hosted on other servers:

Site of SNUC

Prognostic factors

SNUC is a highly aggressive neoplasm
Prognosis is poor, despite aggressive treatment, with a median survival of less than 18 months and a 5 year survival of less than 20% (Am J Surg Pathol 2002;26:371)
Local recurrence is common and is a major cause of morbidity and mortality
Metastatic disease occurs to cervical lymph nodes and to distant sites such as bone, lungs, brain and liver

Treatment

Ideal therapy remains controversial
Intensive multimodal therapy is usually employed, including surgery and adjuvant chemotherapy and radiotherapy

Gross description

Usually > 4 cm
Tend to be fungating, with ill defined borders and frequent invasion into adjacent structures

Microscopic (histologic) description

Hypercellular proliferation, with trabecular, solid, ribbon, lobular and organoid growth patterns
Composed of large, round to oval polygonal cells, with hyperchromatic to vesicular nuclei, inconspicuous to prominent nucleoli and a varying amount of eosinophilic cytoplasm and well defined to poorly defined cell borders
There is increased mitotic activity, including atypical forms
Tumor necrosis is often prominent, both confluent and individual cell necrosis
Apoptosis is common
Lymphovascular invasion and perineural invasion are common
Neurofibrillary material and true neural rosettes are not identified
Squamous or glandular differentiation is usually not present

Microscopic (histologic) images

Contributed by Songyang Yuan, M.D.