Polypoid Ganglioneuroma Masquerading as Rectal Adenoma: Clinical Significance and Literature Review of this Rare Tumor

Abstract

Purpose: Ganglioneuroma (GN) is a rare tumor of the gastrointestinal (GI) tract. It is composed of ganglion cells, nerve fibers, and Schwann cells. Diagnosis is made by immunohistochemical staining, which stains for spindle cells and ganglion cells. Case: A 21-year-old female presented with complaint of persistent hematemesis and hematochezia. EGD and colonoscopy revealed mild gastritis, and two diminutive sessile polyps in the rectum and sigmoid colon. The rectal polyp was suspicious for adenoma, but biopsy showed ganglioneuroma. Discussion: GNs are divided into three categories: 1.) Polypoid Ganglioneuroma (PGN), 2.) Ganglioneuromatous Polyposis (GP), and 3.) Diffuse Ganglioneuromatosis (DG). PGN lesions are solitary or few in number. Endoscopically, they are indistinguishable from hyperplastic and adenomatous polyps. PGN is not associated with increased risk of colon cancer and does not require long-term follow-up. GP is characterized by greater than 20 polypoid lesions microscopically indistinguishable from PGN. GP can be associated with intestinal or extra intestinal manifestations like cutaneous lipomas, skin tags, a syndrome such as Cowden syndrome (CS), juvenile polyposis, and von-Recklinghausen disease. Risk of colon cancer in this category is not firmly established. In a prospective study, 13% patients with Cowden syndrome were associated with colorectal cancer. Patients with GP may require cancer screening. Discussion with patient about possible proctocolectomy can be considered on a case-to-case basis. DG is characterized by mucosal or trans mural proliferation of gangliomeuromatosis tissue, often producing band-like thickening of bowel segments. DG may exist as an isolated finding or can be a component of von Recklinghausen's disease, multiple endocrine neoplasia-2B (MEN 2B). Incidence of DG approaches to 100% in patients with MEN 2B. Chronic constipation or diarrhea is the most common symptom. Diagnosis of DG can lead to early diagnosis of MEN 2B, and can be potentially life-saving. Summary: PGN is not associated with increased risk of colon cancer, and doesn't require any further follow-up. GP and DG can be associated with increased risk of colon and other cancers, and patients may benefit from aggressive surveillance.Figure: Solitary PGN in rectum.