Apocrine gland cyst with hemosiderotic dermatofibroma-like stroma: report of two cases

Two cases of an unusual cutaneous lesion characterized by a dermal nodule with apocrine gland cysts surrounded by a hemosiderotic dermatofibroma-like proliferating stroma are reported. The first case was a 52-year-old female who presented with a nodule on the back of several years of evolution and with the clinical diagnosis of lipoma; the second case was a 41-year-old male who presented with a forehead nodule of several years of evolution with a clinical diagnosis of epidermal cyst. Histologically, an ill-delimited non-encapsulated nodule composed of cystic spaces and solid areas was found. The cystic spaces consisted of ductal structures and a bilayered epithelial covering with apocrine differentiation; the surrounding area showed a stroma composed of a mixture of both fibrocytes and macrophages and abundant hemosiderin granules; foci of recent hemorrhages and a more dense fibrous stroma at the periphery with typical storiform areas were also visible. Both cases have shown a benign course without local recurrence in follow up until this report date.