Lipomatous apocrine mixed tumor of the skin: an unusual giant lesion occurring in the breast

Abstract

Cutaneous mixed tumors (MTs), also known as chondroid syringomas, usually arise as small nodules in the head and neck region. We describe an unusual case of a giant MT measuring 9 cm in its greatest diameter, occurring as a slowly growing pedunculated mass on the breast of a 74-year-old woman. Although MT may rarely occur outside the head and neck region, to the best of our knowledge, this is the first case described in the breast. Apart this unusual clinical presentation, another intriguing feature of tumor was the histological picture, being composed of an extensive mature fatty stromal component closely intermingling with the epithelial structures. As adipocytes were variable in size and focally showed a lipoblast-like appearance, some tumor areas were reminiscent of a well-differentiated liposarcoma, lipoma-like. Based on the histological features, the term 'lipomatous mixed tumor, apocrine type' was proposed for such a lesion. Histogenetic considerations about the lipomatous stromal component of the tumor are provided.