Clear Cell Hidradenoma of Breast Mimicking Atypical Breast Lesion: A Diagnostic Pitfall in Breast Cytology

Clear cell hidradenoma (CCH) is an uncommon skin adnexal tumor arising from eccrine glands. Although several kind of skin adnexal tumors arise in the breast tissue, CCH of the breast is an extremely rare entity. Failure to identify its cytomorphologic features and rarity of this tumor may lead to misdiagnosis on fine needle aspiration cytology. Hereby we report a case of 30-year-old female who presented with painless lump in left breast since 10 months. Fine needle aspiration cytology of lump yielded fluid material. On May-Grunwald-Giemsa stained smears, a possibility of atypical breast lesion was considered and patient was advised a biopsy examination. Final diagnosis of CCH was made on histopathologic examination. Awareness of cytomorphologic features of breast CCH will prevent misdiagnosis as malignant or atypical breast lesions and will allow for correct management of the patients.