A Solitary Sigmoid Perineurioma in an Otherwise Healthy 30-Year-Old Male.

Colorectal perineuriomas are rare benign fibroblastic polyps of the colon found on colonoscopy and usually present as a sessile polyp distal to the splenic flexure. We report a case of sessile sigmoid perineurioma in a young healthy male. He presented with chronic constipation and underwent colonoscopy, which showed a 3-4 mm sessile polyp in the sigmoid colon. Biopsy results were significant for a perineurioma. These polyps are peripheral nerve sheath tumors composed of bland spindle cells with ovoid nuclei in a whorling appearance. The differential diagnosis of these nerve sheath tumors includes ganglioneuromas, schwannomas, neuromas, neurofibroma, or Schwann cell hamartomas, and gastrointestinal stromal tumor (GIST). While these polyps are regarded as benign, it is prudent to rule out other tumors that have malignant potential.