Primary malignant melanoma of the breast: case report and review of the literature

Abstract

Background: Melanoma of the breast is a rare disease and may present as a metastatic manifestation of primary cutaneous melanoma or as primary malignant melanoma of the breast (PMMB). Clinical presentations of PMMB vary and surgery is the mainstay of treatment.

Case report: We present the case of a 54-year-old woman with a primary malignant melanoma of the left breast. She was treated with mastectomy, axillary sentinel lymph node excision and primary reconstruction with a tissue expander. Final histology revealed a malignant melanoma with 10 cm in the largest diameter. Molecular characterization by DNA-sequencing showed B-RAF, N-RAS and c-kit wild types. Immunohistochemical characterization demonstrated weak expression of S100 and melan-A and strong expression of polyclonal S100. HMB45, tyrosine kinase and the cytokeratins AE1/AE3 and MNF 116 were not expressed. Lymphoma-specific markers (CD30, CD3, CD20) and sarcoma-specific markers (desmin, actin, CD34) were also negative. The tumor proliferation rate according to Mib1-staining was 90%. Staging of the abdomen, chest, head and bones showed no evidence of metastases. A dermatological examination showed no primary melanoma of the skin. Interferon-alpha was suggested as adjuvant therapy but declined by the patient. With a follow-up of 6 months, the patient is still alive with no evidence of disease.

Conclusion: PMMB is rare and may be successfully treated with surgical excision. Locally advanced PMMB may occur without regional and distant metastases.

Keywords: Breast cancer; amelanotic; malignant; melanoma; melanotic.