Hyperkeratotic lesion of the nipple revealing cutaneous leiomyoma

BACKGROUND: Leiomyoma of the nipple and areola is a rare benign neoplasm. We report the case of a patient with leiomyoma of the nipple presenting as a hyperkeratotic plaque. OBSERVATION: A 23-year-old patient presented with a five year history of a papillomatous, hyperkeratotic, painful plaque originating in her right nipple. Histological examination of a punch biopsy showed hyperkeratosis of the epidermis with dilatation of the lymphatic vessels within the dermis. Surgical excision revealed a proliferation of smooth muscle fibres, leading to diagnosis of leiomyoma. DISCUSSION: The clinical and histological features were initially consistent with idiopathic naevoid hyperkeratosis of areola. However, associated pain is uncommon in idiopathic lesions. This unusual feature led us to surgical excision enabling the diagnosis of leiomyoma. A hyperkeratotic lesion of the nipple may be associated with benign or malignant neoplasms, hamartoma or chronic dermatoses, or it may be idiopathic. In the present case, the hyperkeratotic lesion revealed subareolar leiomyoma. This is an uncommon clinical presentation not previously seen in medical observations, since leiomyoma usually presents as a firm, painful lump in the subareolar region.