Nasal cavity, paranasal sinuses, nasopharynx
Nasopharyngeal carcinoma
Nonkeratinizing - differentiated

Author: Abul Ala Syed Rifat Mannan, M.D. (see Authors page)
Editor: Songyang Yuan, M.D., Ph.D.

Revised: 18 May 2018, last major update February 2014

Copyright: (c) 2004-2018, PathologyOutlines.com, Inc.

PubMed Search: Nonkeratinizing nasopharyngeal carcinoma differentiated

Cite this page: Mannan, A.A.S.R. Nonkeratinizing nasopharyngeal carcinoma - differentiated. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/nasalnonkeratinizingdiff.html. Accessed August 17th, 2018.
Definition / general
  • Squamous cell carcinoma of the nasopharyngeal mucosa, showing light microscopic or ultrastructural evidence of squamous differentiation
  • One of two subtypes of nonkeratinizing nasopharyngeal carcinoma (NPC), according to WHO classification
Terminology
  • Also known as lymphoepithelioma, transitional carcinoma
Epidemiology
  • ~12% of all NPCs, the least common subtype
  • Uncommon in United States, ~0.25% of all cancers
  • High incidence in Chinese, Southeast Asians, North Africans (e.g. in Algeria and Morocco), native people of Arctic region (in Canada and Alaska)
  • Hong Kong has highest incidence of NPC; 1 in 40 men develop NPC before age 75 years
  • Affects men more than women
  • Peak incidence is in fourth and sixth decades of life
Sites
  • Most common site of origin is lateral wall of the nasopharynx (fossa of Rosenmüller), followed by the superior posterior wall
Etiology
  • Most important factor related to the development of NPC is Epstein-Barr virus (EBV); the strong association indicates a probable oncogenic role (Semin Cancer Biol 2002;12:431)
Clinical features
  • Painless upper cervical lymphadenopathy is the most common presentation
  • Other presenting symptoms include nasal obstruction, nasal discharge, epistaxis, serous otitis media, otalgia, hearing loss
  • Headache and symptoms of cranial nerve involvement are present in advanced disease
Radiology description
  • MRI is the preferred imaging modality for assessing the extent of disease and intracranial extension
Prognostic factors
  • 5 year survival is ~65% for nonkeratinizing NPC (differentiated and undifferentiated subtypes)
  • Tumor stage is the most important prognostic factor; 5 year disease specific survival is 98% for stage I, 95% for stage IIA - B, 86% for stage III and 73% for stage IVA - B
  • Younger age and female gender are associated with better prognosis
  • High plasma / serum EBV DNA titers are associated with advanced stage and active disease; remission is usually associated with very low EBV titers
Treatment
  • Radiation therapy is the mainstay of treatment of NPC of all histologic types
  • Surgery is reserved for patients who fail to respond to radiation therapy
Gross description
  • Varies from smooth mucosal bulge, raised nodule with or without surface ulceration, infiltrative mass lesion or an occult lesion identified only on microscopy
Microscopic (histologic) description
  • Usually interconnecting cords or trabeculae, with little or no keratinization; growth pattern is similar to urothelial carcinoma
  • Tumor cells show well defined cell borders, with variable intercellular bridges
  • Background stroma demonstrates variable lymphoplasmacytic infiltrate
  • Usually no desmoplastic response to invading tumor
  • Subclassification of nonkeratinizing NPC into differentiated and undifferentiated subtypes is optional, as it is not clinically or prognostically significant; if there is overlapping histology within the same tumor, classify according to the dominant component
Microscopic (histologic) images

Images hosted on other servers:

Nonkeratinizing NPC, differentiated

Positive stains
Negative stains
Electron microscopy description
  • Convincing evidence of squamous differentiation - at least some tumor cells show small bundles of tonofilaments and well formed desomsomes
Differential diagnosis
Additional references