RESIDENT CASE STUDIES

September 25, 2003: Case 2  

Table of Contents | List of Diagnoses | Case 1 | Case 2 | Case 3 | Case 4 | Case 5

46 year old African American male with nasopharyngeal mass

Discussion by Kathryn Rizzo, DO, PhD

Nasopharyngeal carcinoma, undifferentiated type, is a squamous cell carcinoma arising from the surface-epithelium of the nasopharynx.This neoplasm has a well established association with the Epstein-Barr virus (EBV).

Incidence: Male predominance

Prevalence: Prevalent in Southeast Asia and Northern Africa, rare in the US and Europe

Distribution: Squamous cell carcinomas and nonkeratinizing carcinomas are common in 60-70 year-olds. Undifferentiated carcinomas often show bimodal distribution: 15-25 year-olds and 60-70 year-olds.

Gross Appearance: Varies, from unidentifiable lesion, to mucosal bulge with overlying intact epithelium, to demonstrable mass with extensive involvement of the surface epithelium.

Microscopic Appearance: 

• 3 Types: 

1. Keratinizing Type 1 - conventional squamous carcinoma with keratinization and intercellular bridges.

2. Nonkeratinizing Type 2 - Stratification of the epithelium composed of cylindrical and spindle-shaped cells. Little or absent keratinization. 

3. Undifferentiated Type 3 (lymphoepithelioma) - See diagnostic criteria.

Diagnostic Criteria

• Prominent non-neoplastic lymphoid component with lymphocytes and occasionally eosinophils
• Syncytial growth pattern composed of cohesive or noncohesive tumor cells
• Tumor cells have:
  •  oval or round vesicular nuclei
  • prominent eosinophilic nucleoli
  • scant cytoplasm
  • indistinct cell margins
  • and increased mitosis
• Absence of keratinization and absent desmoplastic response to invasion
• Inflammatory and neoplastic elements may produce two patterns: 
  • Regaud--neoplastic cells are well-defined, cohesive nests and cords separated by inflammation
  • Schmincke--inflammatory component permeates the cell nests to much greater degree, separating and isolating the carcinoma cells.

Immunostains:

• Tumor cells are cytokeratin positive.

Differential Diagnosis:

• Non-Hodgkin's lymphoma ( large cell or immunoblastic)
• Hodgkin's lymphoma
• Desmoid fibromatosis

References:

1. Haber M. et al, Differential diagnosis in surgical pathology, Copyright 2002.
2. Stephen S Sternberg et al. (Eds): Diagnostic surgical pathology, Volume 1, 3rd edition. Lippincott William & Wilkins.