Epidemiologic, Clinicopathological, Immunohistochemical and Molecular Analysis of Gastrointestinal Glomus Tumors

Glomus tumors are uncommon lesions that may even occur in the gastrointestinal tract. We collected 6 cases of glomus tumors (5 females, 1 male) with a median age of 65.5 years (range 48-86 years) arising from stomach (5 cases) and colon. The tumor sizes varied from 1.5 to 3.5 cm (median 2.5 cm). In our Institutions, the frequency of gastrointestinal glomus tumor is 1 case/57 Gastrointestinal Stromal Tumors (GIST). Histologically and immunohistochemically gastrointestinal glomus tumors are very identical to the conventional soft tissue counterpart, expressing smooth-muscle actin and collagen IV, but not CD117, DOG1, neuroendocrine markers, S100, cytokeratins, desmin. A molecular analysis for c-KIT and PDGFRalpha and PDGFRbeta mutations was performed with negative results by direct sequencing.   Our data confirm that glomus tumors may rarely occur in gastrointestinal tract and differential diagnosis includes several epithelial and mesenchymal tumors, more commonly arising in this site. Histology is quite peculiar, but immunostains may be helpful in differential diagnosis. No mutations were detected in c-KIT and PDGFRalpha and PDGFRbeta.