Background: That sweat gland type tumors occur occasionally in the breast is not surprising, as the breast and cutaneous sweat glands are embryologically related. Cylindromas present most commonly as solitary and sporadic dermal nodules on the face and scalp. Cases of multiple cylindromas are dominantly inherited, and the neoplasms are referred to as "turban tumors" when multiple lesions cover the scalp. Primary cylindroma of the breast has been reported once in the past. To the best of our knowledge, the fine needle aspiration cytology of primary breast cylindroma and its occurrence in the setting of familial cylindromatosis have not previously been reported.
Case: A 59-year-old woman presented with an ill-defined left breast mass. She had a personal and family history of dermal cylindromas on the head and face. Fine needle aspiration cytology demonstrated small, uniform cells with oval nuclei and finely granular cytoplasm, with some cells arranged around conspicuous cylinders of dense, acellular material. Excisional biopsy was recommended to exclude adenoid cystic carcinoma. Tissue biopsy revealed a benign cylindroma arising in breast parenchyma.
Conclusion: Fine needle aspiration cytology of cylindroma very closely mimics that of adenoid cystic carcinoma. Although extremely rare, primary breast cylindroma is another entity to be included in the cytologic differential diagnosis of bland, basaloid cells associated with globular, extracellular material, a finding most commonly associated with adenoid cystic carcinoma.