Characteristics of chronic megacolon among patients diagnosed with multiple endocrine neoplasia type 2B.

Background: Gastrointestinal symptoms are frequent in multiple endocrine neoplasia (MEN) 2B and may be related to megacolon.

Objective: The objective of this article is to review the clinical features of patients with MEN 2B, particularly megacolon.

Methods: We used natural language processing of electronic medical records of Mayo Clinic patients over 20 years: Eight patients with definite MEN 2B were identified; of these, four had megacolon. From these patients' records, three others with paper medical records were identified through familial association. We used a standard data sheet to identify features of the disease with particular emphasis on megacolon.

Results: Of the 11 patients identified with MEN 2B, seven (63%) had megacolon, typically presenting with constipation in infancy or megacolon in childhood. In addition, three patients had esophageal manifestations (two achalasia and one Zenker's diverticulum). Megacolon often required surgical intervention for intractable constipation, abdominal distension and discomfort. Histopathological features of resected colon revealed enteric and extrinsic nerve hyperplasia and ganglioneuromas of the submucosal and myenteric plexuses.

Conclusions: Among patients with MEN 2B, 63% had megacolon. Significant esophageal motor disorders in MEN 2B may affect ∼25% of patients. Any presentation with megacolon should trigger a search for MEN 2B in order to identify the potentially fatal endocrine tumors.