© Georg Thieme Verlag KG Stuttgart · New York
Multiple granular cell tumor of the colon
16 June 2010 (online)
A 44-year-old man was referred to our endoscopy unit because of a family history of colorectal neoplasia. Colonoscopy revealed numerous semi-pedunculated polyps with intact mucosa, measuring 6 – 12 mm, in the cecum (n = 2), ascending (n = 5), and transverse (n = 2) colon. The two largest polyps, measuring 8 mm and 12 mm, respectively, and occurring in the ascending colon ([Fig. 1]), were removed by snare polypectomy. Histologic examination of the polyps revealed a submucosal tumor composed of cells with small round nuclei and abundant granular eosinophilic cytoplasm ([Fig. 2]). Immunohistochemical analysis showed the tumor cells expressed S-100 protein ([Fig. 3]). The resected polyps were diagnosed as granular cell tumor (GCT). Upper endoscopy, enteroscopy by videocapsule, and abdominal computed tomography scan were unremarkable. The patient entered an annual endoscopic follow-up program.
Fig. 1 Narrow-band imaging showed three semi-pedunculated polyps covered by normal mucosa in the ascending colon.
Fig. 2 Histologic examination of the polypectomy specimen showed a submucosal tumor composed of cells with abundant granular cytoplasm. (Hematoxylin and eosin, × 50).
Fig. 3 Immunohistochemical examination for S-100 protein revealed diffuse and strong expression of S-100 protein in tumor cells (× 50).
GCT is a rare tumor that may occur in any site of the body  . It commonly occurs in the oral cavity, the skin, and the subcutaneous tissue, and is seldom found in the gastrointestinal tract  . In the gastrointestinal tract, the most common site is the esophagus, followed by the large intestine  . Gastrointestinal GCT is usually found incidentally during endoscopy as a submucosal tumor and is multiple in 10 % – 20 % of all cases (15 patients described in the literature) .
The final diagnosis of GCT depends on pathologic findings: cells with small, uniform nuclei and abundant granular eosinophilic cytoplasm containing acidophilic, periodic acid-Schiff (PAS)-positive, diastase-resistant granules, and expression of S-100 protein or neuron-specific enolase  .
GCT is usually clinically and histologically benign, with only a few malignant GCT cases reported  . Malignant behavior is suggested by large size (> 4 cm), rapid growth, and invasion of the adjacent tissues rather than the histologic features  . As gastrointestinal GCTs are considered benign, a conservative approach is suggested by means of endoscopic resection and a strict endoscopic follow-up .
Competing interests: None
- 1 Sohn D K, Choi H S, Chang Y S. et al . Granular cell tumor of the colon: report of a case and review of the literature. World J Gastroenterol. 2004; 10 2452-2454
- 2 Rossi G B, de Bellis M, Marone P. et al . Granular cell tumors of the colon: report of a case and review of the literature. J Clin Gastroenterol. 2000; 30 197-199
J. B. Soares, MD
Gastroenterology Department of Braga Hospital
Largo Eng. Carlos Amarante