Ovary, metastatic melanoma

In this case, we are presented with a poorly differentiated epithelioid neoplasm involving the ovary and forming a large expansile mass. The cells have abundant mitotic activity and large round nuclei, with some prominent nucleoli. In some areas, melanin pigment can be appreciated; however, much of the tumour is amelanotic. The differential diagnosis includes primary ovarian cancers, including serous carcinoma, transitional cell carcinoma, and malignant stromal tumours. However, the morphology and presence of melanin pigment should prompt the diagnosis of metastatic melanoma.