Glomus tumor of the cheek: an immunohistochemical demonstration of actin and myosin.

A rare case of a buccal glomus tumor was examined by light and electron microscopy. Histologically, the tumor consisted of various vascular spaces surrounded by masses of epithelioid glomus cells, coexisting with a hemangiomatous proliferation of the vessels. Immunohistochemical stainings revealed that the tumor cells were positive for smooth-muscle actin and myosin, with various intensities of the stainings. The electron microscope invariably showed microfilaments in the tumor cells. The results suggest that the glomus tumor cells have characteristics of the smooth-muscle cell and the tumor has a hamartomatous nature.