Primary Mucinous Carcinoma with Direct Histopathologic Evidence of Lymphatic Invasion

Background: Primary mucinous carcinoma of the skin is a rare sweat gland neoplasm which occurs most commonly in the periorbital region. Although the tumor has a propensity for local recurrence and regional spread, distant metastases are rare. The standard treatment of primary mucinous carcinoma is wide local excision. Mohs micrographic surgery may also be utilized in cases where tissue conservation is of utmost concern. Objective: We present a case of primary mucinous carcinoma arising in the scalp, which was treated with wide local excision. Methods: A case report and literature review are presented. Results: Histopathologic evaluation revealed a well-circumscribed neoplasm characterized by lobules and aggregates of epithelial cells embedded in abundant pools of mucin. In addition, small aggregates of neoplastic cells were found at a distance from the primary nodule, indicative of lymphatic invasion. Conclusion: Primary mucinous carcinoma has a high propensity for locoregional metastases and recurrence. To our knowledge, this is the first report demonstrating direct histopathologic evidence of lymphatic invasion which correlates with this tumor’s biologic behavior.