Glomus tumor. A histological, histochemical and immunohistochemical study of the various types.

Glomus tumors are benign lesions composed of vessels and glomocytes in varying proportions. The histological appearance of the tumors depend upon the ratio of the vascular to the glomus cells and their differentiation as well as upon the amount and composition of the stroma. The aim of the present study was the establishment of criteria for the distinction of glomus tumor-like malformations from neoplasms with glomus cell differentiation. Using a panel of monoclonal and polyclonal antibodies (vimentin, a-smooth muscle actin, desmin, pan-keratin, low molecular weight cytokeratin, EMA, NSE, S-100 protein, Factor VIII, a1-ACT) glomus tumors could be separated into three types: vascular, cellular with myxoid stroma and cellular, solid type. In the first two types the tumor growth is composed of all three components found in normal glomus body, but in a haphazard fashion and thus might be considered as tumor-like malformations. The third type is composed of perivascular arranged cells most of which acquire the phenotypical characteristics of glomocytes. This last tumor probably represent the neoplastic variant of the group of lesions designated by the term glomus tumor.