Colonic granular cell tumor: Report of 11 cases and management with review of the literature

Abstract

Colonic granular cell tumors (GCTs) are rare and benign, but have malignant potential. The recent progress in endoscopic procedures and technology facilitate the diagnosis and treatment of GCTs. The present study described 11 cases of colonic GCTs diagnosed between March 2010 and April 2015, including patient clinical and histopathological features. Patients were generally asymptomatic. The most common symptoms were hematoquezia and abdominal pain. The male/female ratio was 7:4; age range was 40-67 years. Colonoscopy revealed a yellowish or white, solid and well-circumscribed tumor covered by normal mucosa. Endoscopic ultrasonography (EUS) showed a homogenous, or granular-type heterogeneous, hypoechoic solid tumor originating from the submucosal layer (8 cases) or muscularis mucosae (3 cases), with maximum diameters 0.3-3.0 cm. All patients underwent endoscopic submucosal dissection or endoscopic submucosal excavation without complication. All tumors were block removed. The mean operative time was 38 min (range, 31-50 min). Immunohistochemical analysis of all specimens confirmed the diagnosis of GCT by positive staining of S-100 protein. No recurrence or metastasis was observed during follow-up periods of 11 months to 5 years. In conclusion, colonoscopy, EUS and immunohistological examination increase the accuracy of diagnosis of GCTs. Endoscopic management is feasible and safe for GCT treatment.

Keywords: colonic granular cell tumor; endoscopic submucosal dissection; endoscopic submucosal excavation; endoscopic ultrasonography.

Figure 1.

ESD procedure. (A) Submucosal injection of mixed solution around the lesion to lift the tumor. (B) Submucosal dissection of the lesion. (C) Wound appearance. (D) Wound closing using clips. ESD, endoscopic submucosal dissection.

Figure 2.

ESE procedure. (A) Submucosal injection of mixed solution and mucosectomy. (B) Wound surface. (C) Wound closure with clips. ESE, endoscopic submucosal excavation.

Figure 3.

Colonoscopy and EUS image of colonic GCTs. (A) Colonoscopic view of a 0.4-cm GCT located in the ascending colon. (B) Colonoscopic view of a 3.0-cm GCT located in the cecum. (C) Homogenous and hypoechoic lesion originating from muscularis mucosa, by EUS. (D) GCT image by EUS, showing granular-type heterogeneous and hypoechoic lesion confined to the submucosal layer. EUS, endoscopic ultrasonography; GCTs, granular cell tumors.

Figure 4.

Histologic features of colonic granular cell tumor. (A) Hematoxylin and eosin showing ribbons of round-to-polyhedral cells that were characterized by small, uniform nuclei surrounded by abundant granular eosinophilic cytoplasm (original magnification, ×200). (B) Immunohistochemical analysis revealed positive staining of S-100 in the nucleus and cytoplasm (original magnification, ×200).