Mast cells in solitary glomus tumors: a possible algogenic role.

Mast cells in three cases of solitary glomus tumor were examined by light and electron microscopy. As seen by light microscopy, a number of round, oval or elongated mast cells were distributed throughout the stromal connective tissue and showed slight or moderate metachromasia when stained with toluidine blue (pH 4.1). Electron microscopy revealed various types and degrees of degranulation of mast cell granules, and also disclosed a close correlation between mast cells and non-myelinated nerve fibers. These findings suggest that mast cells may play an algogenic role in solitary glomus tumors, probably mediated by the contents, mainly histamine, concentrated in their granules.