Nasal cavity, paranasal sinuses, nasopharynx
Sinonasal carcinoma
Sinonasal undifferentiated carcinoma

Topic Completed: 1 December 2013

Minor changes: 13 April 2021

Copyright: 2004-2021,, Inc.

PubMed Search: Undifferentiated anaplastic carcinoma sinonasal[TI]

Rifat Mannan, M.D.
Songyang Yuan, M.D., Ph.D.
Page views in 2020: 12,137
Page views in 2021 to date: 5,060
Cite this page: Mannan R, Yuan S. Sinonasal undifferentiated carcinoma. website. Accessed May 10th, 2021.
Definition / general
  • Rare, highly aggressive and clinicopathologically distinct malignancy of uncertain histogenesis
  • Sinonasal undifferentiated carcinoma (SNUC)
  • Undifferentiated (anaplastic) carcinoma
  • 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)
  • 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
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
  • 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.

Lobules of pleomorphic tumor cells

Strong reactivity for CK AE1 / AE3

Images hosted on other servers:

Spindly cells admixed with lymphoid cells

Large, round / polygonal cells

Positive stains
Negative stains
Electron microscopy description
  • Rare dense core granules in individual cells
Back to top
Image 01 Image 02