A case of cutaneous malignant glomus tumor

Glomus tumors are well-known but relatively rare vascular neoplasms, with their malignant counterparts still being rarer. There are very few reports of cutaneous malignant glomus tumors, and the current limited evidence suggests that they follow a more indolent course than deep-seated malignant glomus tumors. Herein, we are reporting a case of cutaneous malignant glomus tumor. A 94-year-old male presented with a right-sided ulcerated scalp lesion, which, on biopsy, showed a diffusely infiltrative epithelioid malignancy with considerable pleomorphism and a notable perivascular growth pattern. The tumor cells were positive for smooth muscle actin (SMA) and h-caldesmon, and negative for cytokeratin MNF116, CK5, p40, S100, SOX10, HMB45, Melan-A, ERG, CD31, CD45, CD3, CD20, ALK, desmin, CD68, CD34, and HHV8. A diagnosis of cutaneous malignant glomus tumor was made, and the patient underwent a wider excision. Cutaneous malignant glomus tumors are extremely rare and should be considered when examining unusual cutaneous mesenchymal tumors.