1601 Cecal Granular Cell Tumour: An Uncommon Site of an Uncommon Tumour

Abstract

INTRODUCTION: Granular Cell Tumors (GCTs) are tumors arising from Schwann cells of the nerve sheath. They occur at an incidence of about 0.03% and have a predilection for the skin, oral cavity, and breasts. Only 6-8% of all GCTs occur in the GI tract with the esophagus (65%) being the most common site, followed by the colorectum (25%). Less than 20 cases of cecal GCTs have been reported so far. Owing to its rarity, we report a case of an asymptomatic cecal GCT found incidentally during screening colonoscopy. CASE DESCRIPTION/METHODS: A 58-year-old male with no known past medical history presented to the Gastrointestinal (GI) clinic for screening colonoscopy. History was negative for alarm symptoms, including no family history of GI cancers. He had no prior Upper endoscopy or colonoscopy. Physical examination and labs were unremarkable. Colonoscopy revealed an 8mm yellowish, sessile, subepithelial nodule with normal overlying mucosa in the cecum (Figure 1). Biopsy showed clusters of cells with granular cytoplasm that was Periodic acid–Schiff (PAS) positive suggestive of GCT (Figure 2). Immunohistochemical staining was positive for S100, CD 68, calretinin thus confirming the diagnosis of GCT (Figure 3). The patient has since been scheduled for Endoscopic ultrasound (EUS) for further evaluation. DISCUSSION: Colorectal GCTs account for up to 25% of all GI GCTs, with most affecting the right sided colon (cecum and ascending colon). Mostly benign and solitary, but about 2% are known to have malignant potential with poor prognosis. More common in females and in African Americans between ages 40-60 years. Generally asymptomatic and found incidentally during a screening colonoscopy, however in a few cases, patients have presented with hematochezia, abdominal pain, and change in bowel habits. EUS is invaluable in differentiating GCTs from other subepithelial tumors, in determining the size, and depth of invasion. Definitive diagnosis is by histopathology and immunohistochemical staining. There is no general consensus on the management of colorectal GCTs. Conservative management is recommended for tumors < 1cm, asymptomatic, with no deep tissue invasion or malignancy. However, resection is warranted for symptomatic tumors, tumors >1 cm in size, deep tissue invasion or malignancy. Endoscopic removal is preferred over surgery for tumors without deep tissue infiltration or malignancy. Endoscopic and histologic surveillance every 1-2 years is recommended.