Cutaneous squamous cell carcinoma associated with proliferation of osteoclast-like giant cells.

Proliferation of osteoclast-like giant cells in a cutaneous squamous cell carcinoma is a rare phenomenon and so far only four cases have been reported. In previous reports, osteoclast-like giant cells were admixed with sarcomatoid component of squamous cell carcinoma and it is therefore debatable if the osteoclast-like giant cells represent a reactive phenomenon or a part of the malignant tumour. A case of cutaneous squamous cell carcinoma associated with osteoclast-like giant cells is reported. However, sarcomatous component of squamous cell carcinoma was not identified in this case. Morphologically, the osteloclast-like giant cells appeared to be benign. The localization of the squamous cell carcinoma and the osteoclastic-like giant cells were separate from one another. Immunohistochemically, squamous cell carcinoma was positive for high molecular weight cytokeratin, cytokeratin-5 and p63, whereas the osteloclast-like giant cells were positive for histiocyte marker CD68 and vimentin and negative for epithelial markers supporting a reactive nature of osteoclast-like giant cells to the cutaneous malignancy.