Clear-cell hidradenoma in a child: a diagnostic dilemma for the cytopathologist

Primary cutaneous tumors are infrequently subjected to fine needle aspiration cytology. As a result, the cytological reports of skin adnexal tumors like hidradenoma are scarce in the available literature. A young boy with a painless nodule on forehead underwent fine needle aspiration. The smears showed clusters of epithelial cells containing blue cytoplasm, some of which had vacuolated cytoplasm with mild nuclear pleomorphism and occasional larger hyperchromatic nucleus. The cytological features, in conjunction with the clinical examination, suggested a skin appendageal tumor. Though nuclear pleomorphism and occasional larger nucleus posed a cytological diagnostic challenge, a diagnosis of benign appendageal tumor was suggested, considering the young age of the patient. This was later confirmed as a clear-cell hidradenoma on excision biopsy. The cytopathologist should consider skin appendageal tumors during evaluation of cutaneous nodules. An accurate diagnosis requires a close clinico-pathologic correlation.