Wasserman JK, Sekhon HS, Ayroud Y. Malignant Melanoma With Osteoclast-Like Differentiation.
Int J Surg Pathol 2015;
23:478-82. [PMID:
26113663 DOI:
10.1177/1066896915592016]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Osteoclast-like giant cells are frequently encountered in nonskeletal malignancies; however, the evidence to date suggests that they represent a tissue response to the lesion rather than neoplastic differentiation. We describe a case of metastatic melanoma demonstrating osteoclast-like differentiation in the lung. The lung nodule was diagnosed as a metastatic melanoma by histological features and confirmed by immunohistochemistry. Resection specimen showed numerous multinucleated giant cells exhibiting osteoclast-like morphology dispersed throughout the lesion. Both the neoplastic melanocytes and giant cells were reactive for HMB-45, Melan-A, and S100. In addition, the multinucleated neoplastic giant cells were also reactive for the monocyte/macrophage lineage markers CD68 and CD163, and alkaline phosphatase, an enzyme present in normal osteoclasts. The neoplastic melanocytes and the multinucleated neoplastic giant cells were also reactive for microphthalmia-associated transcription factor, a protein required for the development of both melanocytes and osteoclasts. Collectively, a co-expression of monocyte/macrophage markers along with melanocytic markers and alkaline phosphatase in the multinucleated neoplastic giant cells in metastatic melanoma suggest that malignant melanocytes are capable of differentiating into osteoclast-like cells and consequently aid invasion into various structures and eliciting the aggressive behavior.
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