A 92-year-old woman presented with a nodule on her left inner thigh. An excisional biopsy specimen demonstrated an intradermal multinodular tumor composed of admixed polygonal to spindle cells, osteoclastlike multinucleated giant cells, extravasated erythrocytes, hemosiderin deposition, and foci of osteoid formation (Figure). Immunohistochemical analysis showed that multinucleated giant cells were markedly positive for CD68 and Ham56 and weakly positive for factor XIIIa and MAC387. Human telomerase reverse transcriptase (hTERT) analysis showed granular cytoplasmic staining, but negative nuclear reactivity. Tumor cells tested negative for S-100, MART-1, and all cytokeratins in the panel. Appropriate positive and negative controls were included. A diagnosis of giant-cell tumor (GCT) of skin was made. The patient had no history of a bone tumor and showed no clinical evidence of tumor recurrence as of her last follow-up.
Murphy M, Kerr P. Giant-Cell Tumor of Skin With Cytoplasmic Human Telomerase Reverse Transcriptase Expression. Arch Dermatol. 2011;147(3):359-361. doi:10.1001/archdermatol.2011.40