Primary Cutaneous Mucinous Carcinoma: A Case Report and Review of the Literature

Primary cutaneous mucinous carcinoma is a rare adnexal tumor arising from the sweat glands. It is usually located at the cephalic extremity, especially the periorbital region. We report the case of a patient who presented with primary mucinous carcinoma of my axillary region. The histological study showed a poorly differentiated and infiltrating carcinoma requiring an immunohistochemical study, which subsequently showed an appearance in favor of a malignant adnexal tumor of the primary mucinous cutaneous carcinoma type with Cytokine 7 positivity, ER at 60%, PR at 40%, androgen receptor positivity at 30% and negativity of Cytokine 20. Primary cutaneous mucinous carcinoma is difficult to differentiate from breast or gastrointestinal metastasis. The presence of carcinoma in situ or myoepithelial cells is in favor of a primary cutaneous origin. It is a slow-growing tumor, with exceptional metastasis. The treatment is surgical and the recurrence rate is very high. Through these two observations, the authors highlight the main clinical, histological and therapeutic aspects of this entity with a review of the literature.