Granular cell tumor of the gastrointestinal tract: histologic and immunohistochemical analysis of 98 cases.

Granular cell tumors (GCTs) are uncommon benign neoplasms in the gastrointestinal (GI) tract, and our current understanding of GCT in GI tract is limited. A total of 98 GCTs were retrieved from 95 patients, and the clinicopathological and immunohistochemical features were compared. The male-to-female ratio was 2.2:1 and with a mean age of 49 years. The mean tumor size was 0.37 cm. Seventy-three esophageal (75%), 21 colorectal (21%), and 4 gastric (4%) GCTs were included. Gastric (mean, 0.75 cm) and colorectal (0.6 cm) GCTs were significantly larger than esophageal tumors (0.27 cm; P<.001). Colonic and gastric GCTs showed a more infiltrative growth pattern (P<.001) and peritumoral lymphoid cuffs (P<.001) than esophageal tumors. Involvement of mucosa, submucosa, and both were noted in 58 cases (59%), 11 cases (11%), and 28 cases (29%), respectively. One GCT from the sigmoid colon (1%) had infiltration to pericolic soft tissue and with lymph node metastasis. High frequency of immunolabeling for S-100 protein (81/81, 100%), CD56 (55/58, 95%), CD68 (58/61, 95%), SOX-10 (54/58, 93%), and inhibin-α (30/58, 52%) were observed. In summary, GCTs in the GI tract were observed with the following frequency: esophagus, colorectum, and stomach. Colorectal and gastric GCTs were larger and had infiltrative growth and more lymphoid cuffs than esophageal GCTs. Although invasive GCT was rare, it could be observed in the GI tract. Inhibin-α expression were more common in colonic GCTs than esophageal tumors. High S-100 protein, CD56, CD68, and SOX-10 expression rates were observed in GCTs from GI tracts.