Clear cell hidradenoma of the breast: a case report with review of the literature.Breast Cancer. 2007;14(3):307-11.

Clear cell hidradenoma of the breast is rare. A 55-year-old woman demonstrated a left breast tumor during follow-up examination of the right breast. Focal asymmetric density was shown on mammogram, and ultrasonography showed an intracystic tumor. Since the diagnosis was not clear on aspiration cytology, excisional biopsy was performed. The lesion was an intracystic tumor macroscopically. Histological examination demonstrated characteristic histological features of clear cell hidradenoma, such as proliferation of uniform epithelial cells, clear or slightly eosinophilic cytoplasm, and cuboidal cell-lined ductal structures. Immunohistochemically, these proliferating epithelial cells were negative for myoepithelial markers, such as alpha-smooth muscle actin, CD10 and anti-muscle actin, but positive for p63. These features were consistent with clear cell hidradenoma.

Mucinous hidradenoma: a report of three cases.: J Cutan Pathol. 2007 Jun;34(6):497-502.

Mucinous cutaneous adnexal tumors are an uncommon occurrence. We describe three cases of mucinous hidradenoma characterized by diffuse and prominent mucinous cell proliferation and discuss the relevant literature. The patients (two men and one woman) ranged in age from 32 to 72 years. The lesions were completely excised, and all patients were alive without evidence of disease (follow-up interval 3-4 years). Case 1 presented as a 1.3-cm eyelid nodule and histology showed a mucinous apocrine hidradenoma with a proliferation of mucinous cells and apocrine glands. Case 2, from the shoulder of a 40-year-old man, was a 2.5-cm well-circumscribed nodule composed of hyperplastic villoglandular proliferation of mucinous cells with focal squamous whorls and focal columnar glandular cells showing decapitation secretion. The tumor was also interpretated as a mucinous hidradenoma, most likely of follicular-apocrine origin. Case 3 was a 3.0-cm scalp nodule. The histology showed a mucinous clear-cell hidradenoma composed of numerous mucinous glands amidst small squamous cells with clear cytoplasm and a hyalinized fibrovascular stroma.