P4722 - Mucosal Schwann Cell Hamartoma in the Transverse Colon: A Rare Finding and Location

Michael S. Owolabi, DO¹, Rahul Patel, DO², Edward Bley, DO², Marisa Pope, DO², Seth Lipshutz, DO², Christopher Chhoun, DO², Ikhtesham Chaudhry, DO², Drew Chiesa, DO²
1Jefferson Health, Voorhees, NJ; 2Jefferson Health, Sewell, NJ

Introduction:

Mucosal Schwann cell hamartomas (MSCHs) in the gastrointestinal tract (GIT) are highly rare to the point that there is no data on its incidence and prevalence. Its prevalence has predominantly been demonstrated in the GIT via literature case reports.  They are typically incidental findings during colonoscopy and are not associated with malignancy or inherited syndromes.

Case Description/

Methods:

A 60-year-old African American female with a history of paroxysmal atrial fibrillation, hypertension, and hyperlipidemia presented for a screening colonoscopy. She has a family history of colon cancer in her mother of unknown histology. She drinks alcohol socially and has never smoked tobacco. She has been compliant with her colonoscopy screenings with her last one being 5 years prior demonstrating benign polyps in the transverse colon and internal hemorrhoids. She presented with no new complaints. During this colonoscopy, a single 4mm sessile transverse polyp was removed. The biopsy demonstrated the proliferation of bland spindle cells, positive for S100 and negative for CD68 and AE1/AE3, which was consistent with MSCH. She was counseled on the benign nature of the tumor and recommended to follow up with a repeat colonoscopy in 5 years.

Discussion:

MSCH is a rare, benign lesion that is asymptomatic when present. Although they are scarce in the GIT, when present they are detected as small polyps ranging from 1 to 8mm and predominantly located in the rectosigmoid region. They are composed of bland spindle cells arranged in vague fascicles with S-100 positivity. At this time, there is no belief that MSCHs are related to inherited syndromes or malignancies. The differential diagnosis of these lesions is broad. This case demonstrates the importance of pathology to avoid mistaking it for gastrointestinal stromal tumors, colorectal neurofibromas, mucosal neuromas, gastrointestinal ganglioneuromas, gastrointestinal schwannomas, mucosal perineuromas, and inflammatory fibroid polyps.


Figure: Image 1: Sessile polyp with histopathology consistent with MSCH

Disclosures:
Michael Owolabi indicated no relevant financial relationships.
Rahul Patel indicated no relevant financial relationships.
Edward Bley indicated no relevant financial relationships.
Marisa Pope indicated no relevant financial relationships.
Seth Lipshutz indicated no relevant financial relationships.
Christopher Chhoun indicated no relevant financial relationships.
Ikhtesham Chaudhry indicated no relevant financial relationships.
Drew Chiesa indicated no relevant financial relationships.

Michael S. Owolabi, DO¹, Rahul Patel, DO², Edward Bley, DO², Marisa Pope, DO², Seth Lipshutz, DO², Christopher Chhoun, DO², Ikhtesham Chaudhry, DO², Drew Chiesa, DO². P4722 - Mucosal Schwann Cell Hamartoma in the Transverse Colon: A Rare Finding and Location, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.