Salivary gland tumors with a prominent oncocytic component. Cytologic findings and differential diagnosis of oncocytomas and Warthin's tumor on fine needle aspirates.
OBJECTIVE
To review aspirates from histologically documented oncocytomas and Warthin's tumor (WT) to highlight the cytomorphologic findings and determine the difficulties encountered in typing oncocytepredominant aspirates.


METHODS
Over a 19-year period (1982-2000) we reviewed aspirates from 45 cases with an oncocyte preponderance. In 24 of them tissue for histologic examination was available (5 oncocytomas and 19 WT).


RESULTS
In 4 of the 5 histologically documented oncocytomas the aspirates were cellular, with oncocytic epithelial cells in sheets, papillary fragments and singly. Epithelial atypia was minimal and lymphoid component absent, though scant proteinaceous material with a sprinkling of lymphocytes was seen. In WT moderate (35%) to abundant (28%) oncocytic epithelial cells were seen predominantly in a sheetlike arrangement with occasional papillary fragments and single cells. A variable quantity of lymphoid component was seen in 90% of the aspirates, with 88% of them showing a proteinaceous background accompanied by necrotic debris in 43% of cases. Squamous metaplasia was identified in 30% of cases, with 3 showing atypical squamous cells. In four cases the lymphoid component was scant and oncocytes abundant, and both possibilities were entertained.


CONCLUSIONS
Fine needle aspiration cytology is fairly accurate in the preoperative diagnosis of WT. When the lymphoid component, mucus and necrotic background are minimal or absent, the tumors can be confused with oncocytoma. In oncocytoma, the oncocytic epithelial cells are more often seen in papillary fragments, acini and singly in comparison to WT, where sheets of oncocytic cells are observed. Some degree of epithelial atypia can be seen in oncocyte-predominant benign lesions. Squamous metaplasia, especially if accompanied by atypia and necrosis, can prove challenging.
Verma
Kusum
K
Cytology Laboratory, Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110029, India.
Kapila
Kusum
K
D000235:Adenolymphoma / Q000473:pathology*; D018249:Adenoma, Oxyphilic / Q000473:pathology*; D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D002648:Child; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control*; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008679:Metaplasia / Q000473:pathology; D008875:Middle Aged; D012468:Salivary Gland Neoplasms / Q000473:pathology*; D012469:Salivary Glands / Q000473:pathology*