Metastatic Melanoma Resembling a Fibrohistiocytic Tumor with Osteoclast-like Giant Cells
Alexander Wong, MD1, Manju Prasad, MD1, Stephan Ariyan, MD3, and Rossitza Lazova, MD1, 2
Departments of 1Pathology, 2Dermatology, and 3Plastic Surgery, Yale School of Medicine, New Haven, CT, USA
INTRODUCTION
Numerous histopathologic variants of malignant melanoma (MM) exist. The presence of osteoclast-like giant cells (OCG) in MM has rarely been reported in the literature and may result in a misdiagnosis of a histiocytic tumor. Malignant neoplasms containing OGCs are rare and the origin of these cells is often disputed. Molecular studies of OGCs in tumors of the pancreas and the liver have demonstrated the same K-ras mutation as dysplastic ductal epithelial cells suggesting that they may represent transformed tumor cells.1 On the other hand, studies of OGCs in tumors of various organs including skin, observed that the giant cells expressed several monocyte/macrophage mark-ers including leukocyte common antigen and CD68, suggesting that these cells are reactive histiocytes rather than neoplastic. Since only few cases have been reported, awareness of this entity is important to avoid misdiagnosis of melanoma as a histiocytic tumor.
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