EP315 - Colonic Schwannoma

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Purpose/Background: Schwannomas are a nerve sheath tumor arising from the Schwann cells which envelope peripheral nerves. These tumors rarely occur in the gastrointestinal tract with the lowest frequency in the colon and rectum. Often found incidentally on colonoscopy or abdominal imaging, the diagnosis is confirmed with immunohistochemical staining. This report documents the case of a 60-year-old female referred to gastroenterology for an incidentally noted 3 cm colonic mass. The mass was noted on a CT scan of the chest for the patient’s known emphysema secondary to prior tobacco use disorder.

Methods/Interventions: The patient underwent an endoscopic ultrasound with gastroenterology which localized the mass to the descending-sigmoid junction. The mass was biopsied and the site tattooed. Biopsy results came back for a colonic schwannoma based on immunohistochemistry and the patient was referred to colorectal surgery for further management.

Results/Outcomes: The patient underwent an uneventful robotic partial colectomy and recovered well post-operatively, discharging home on post-op day 1. Final pathology confirmed the diagnosis of a colon schwannoma based on strong staining for S-100 and negative staining for DOG-1. Zero of seven lymph noted were positive.

Conclusion/Discussion: Colonic schwannomas are an exceedingly rare submucosal tumor of the colon and rectum. Often found incidentally, these tumors are typically asymptomatic, but a complete understanding of their clinical progression is unknown due to their rarity. If diagnosed, these tumors should be resected in order to allow for definitive pathologic review and to rule out malignancy.