Aspiration cytology in the diagnosis of primary tumors of skin adnexa.

OBJECTIVE

To evaluate the cytologic features and pitfalls in the cytodiagnosis of certain tumors of skin adnexa.

STUDY DESIGN

Smears from five nodular basal cell carcinomas, two chondroid syringomas and one case each of primary mucinous carcinoma, Merkel cell tumor, trichoepithelioma, pilomatrixoma and eccrine spiradenocarcinoma, all histologically confirmed, were evaluated with special attention to cytologic features that may aid the diagnoses.

RESULTS

Ten of 12 (83.3%) adnexal tumors were correctly recognized on aspiration cytology. The five basal cell carcinomas were atypical in presentation and clinically unsuspected but were diagnosed on cytology. The chondroid syringomas and Merkel cell tumor could also be diagnosed due to awareness of the cytologic features and sound clinical correlation. The eccrine spiradenocarcinoma was diagnosed as spiradenoma because of improper assessment of local invasion and incorrect mitotic count in the aspirates. The diagnosis was inaccurate in primary mucinous carcinoma as the aspirate yielded mainly mucin.

CONCLUSION

Although exact subtyping of tumors of skin adnexa may not always be essential, certain benign adnexal tumors have aggressive counterparts (e.g., eccrine spiradenomas), while others clinically mimic metastases or small round cell carcinomas (e.g., Merkel cell tumors). Thus, correct cytodiagnoses and awareness of the limitations of cytology (such as in the assessment of local invasion) in these instances help to outline surgical management.