Lankenau Medical Center Wynnewood, PA, United States
Julianna Tantum, DO, Vida Chen, MD, Gary Newman, MD Lankenau Medical Center, Wynnewood, PA
Introduction: Mucosal Schwann Cell Hamartomas (MSCH) are rare, benign colon polyps. They were first described in 2009, and since then, about a dozen cases have reported this rare pathological finding in colonic polyps. We present a case of an asymptomatic female, with no past history of inherited disorders, who was found to have four colonic polyps with pathological evidence of MSCH.
Case Description/Methods: A 58-year-old female with a past medical history of hypertension, pre-diabetes, and mild intermittent asthma presented for a screening colonoscopy. The patient denied nausea, vomiting, abdominal pain, hematochezia, or melena. She denied a family history of colon cancer. The patient had a colonoscopy five years prior, which showed evidence of one 25 mm tubular adenoma in the mid-ascending colon.
The patient had a good prep and the colonoscope was advanced to the cecum. A 4 mm sessile polyp was found in the proximal descending colon and removed with cold biopsy forceps. Two 5 mm sessile polyps were found in the distal descending colon and removed using cold biopsy forceps (Figure 1A). A 3 mm sessile polyp was found in the sigmoid colon and removed with cold biopsy forceps.
The lesional cells were found to stain positive for S100 and negative for epithelial membrane antigen (EMA) and smooth muscle actin (Figure 1B). On H&E stain, bland spindle cells were found expanding the lamina propria, thus identifying these polyps as Mucosal Schwann Cell Hamartomas. The patient was planned to follow up for a repeat screening colonoscopy in ten years.
Discussion: MSCH are a rare form of colon polyps but have become increasingly recognized over the past few years. They are derived from mesenchymal cells and are most commonly found in the rectosigmoid region, though they may arise anywhere in the colon. These polyps are noted to appear similar to other polyps in the colon, most often described as sessile polyps measuring 1-6 mm in size. Average patient age is 62 years with a female predominance. Diagnosis requires biopsy and immunohistochemistry showing strong positive staining for S100 and negative for EMA. These benign, incidental spindle cell lesions composed of Schwann cells have no association with any hereditary disorders, and patients should follow the normal guidelines for surveillance.
Gibson JA, Hornick JL. Mucosal Schwann cell "hamartoma": clinicopathologic study of 26 neural colorectal polyps distinct from neurofibromas and mucosal neuromas. Am J Surg Pathol. May 2009;33(5):781-7.
Figure: Image 1. A. Two descending colon polyps. B. Positive (brown) S100 staining in lesional cells. C. H&E stain of bland spindle cells expanding the lamina propria.
Disclosures: Julianna Tantum indicated no relevant financial relationships. Vida Chen indicated no relevant financial relationships. Gary Newman indicated no relevant financial relationships.
Julianna Tantum, DO, Vida Chen, MD, Gary Newman, MD. P1266 - Colonic Mucosal Schwann Cell Hamartomas: A Case Report on a Rare, Benign Pathological Finding, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.
