Abstract

A 92-year-old female presented to multidisciplinary melanoma clinic for a newly diagnosed invasive melanoma of the right forehead. Prior excision had shown both melanoma with superimposed poorly differentiated carcinoma. During her evaluation, a right breast mass and right axillary lymphadenopathy were palpated. Subsequent biopsy of the right breast mass confirmed invasive ductal carcinoma and further workup revealed metastatic disease. Review of her outside slides revealed a neurotrophic lentigo maligna melanoma invasive to a Breslow depth of 3.0 mm with superimposed poorly differentiated carcinoma. Immunohistochemical studies were performed, with a Mart-1 immunostain confirming the primary melanoma. The concurrent proliferation of poorly differentiated epitheloid cells was negative for Sox10 and positive for AE1/AE3, CK7, GCDFP and GATA3. Given the clinical context and immunohistochemical profile, a cutaneous metastasis of her metastatic breast carcinoma was diagnosed, which had localized to her primary melanoma. Increased risk of cutaneous melanoma in breast cancer patients has previously been reported. Genetic alterations, common among both tumors, are thought to be responsible for synchronous breast cancer and melanoma. However, we were only able to identify one similar case in the literature, in which both cutaneous lobular breast cancer metastases and melanoma metastases were identified in the same scalp tumor. Our case is unique given localization of cutaneous breast cancer metastases to a primary melanoma. The uniqueness of this case may be pathophysiologically explained by increased blood supply due to deeply invasive tumor and anatomic site on the head, a location known for its robust vascular supply.

Financial Disclosure:
No current or relevant financial relationships exist.