Case 104 - Discussion

Uploaded: 2007-08-14, Updated: 2007-08-14

   

Warthin's Tumor (Papillary Cystadenoma Lymphomatosum)

DEFINITION

 
  • An adenoma,  bilayered columnar and basaloid oncocytic epithelia that form multiple cysts with numerous papillations; proliferation of follicle-containing lymphoid tissue.

CLINICAL FEATURES

 
  • Second most common benign parotid tumor, 4-11.2% of all parotid tumors;

  • Almost exclusively in parotid glands; male predominance; average age 60 year-old;

  • Painless, fluctuant, swelling mass.

GROSS FINDINGS

 
  • Spherical, oval, well-circumscribed;

  • Variable cysts in the cut surface, small slit-like space to several centimeters; The lining  of the cysts has small, knob-like excrescence.

MICROSCOPIC FINDINGS

 
  • Thin capsule, sharp demarcation;

  • Cysts lined by a papillary proliferation of bilayered oncocytic epithelium with a supporting stroma of extensive lymphoid tissue;

  • Luminal epithelium: tall columnar oncocytic cells, palisading of oval nuclei that are in the center or apical of the cells; Cytoplasm is finely granular and brightly eosinophilic;

  • Basaloid cells: beneath the columnar cells, smaller, triangular; finely granular eosinophilic cytoplasm;

  • Epithelial cells form shape papillae in variable size that project into the luminal spaces;

  • Supporting stroma: dense lymphoid tissue, predominantly small lymphocytes, germinal follicle in half of the cases;

  • May show necrosis, infarction, squamous or mucoid metaplasia, atypical changes, or malignant transformation into carcinoma or lymphoma.

DIFFERENTIAL DIAGNOSES

 
  • Papillary oncocytic cystadenoma.

IMMUNOHISTOCHEMISTRY AND SPECIAL STAINS

 
  • Both luminal and basal cells are negative for vimentin, GFAP and monoclonal S100.

ELECTRON MICROSCOPIC FINDINGS

 
  • Both luminal and basal cells show abundant mitochondria.

REFERENCES