Absence of rectoanal inhibitory reflex in a child with multiple endocrine neoplasia type 2B

Patients with multiple endocrine neoplasia (MEN) type 2B inherently present with gastrointestinal motility disorders as well as medullary thyroid carcinoma, adrenal pheochromocytoma, and Marfanoid habitus.

The authors examined gut motility function in a 7-year-old girl with MEN type 2B who had suffered from chronic constipation and recurrent acalculous cholecystitis since infancy.

Results of total gastrointestinal barium meal and enema studies showed marked hypoperistalsis of the gut and entire colonic dilatation. Histopathologic study results of the gut wall from the stomach, duodenum, and rectum showed hyperplasia of the submucosal and intramuscular neural plexuses in all specimens. Anorectal manometry demonstrated disarrangement of the internal sphincter rhythmic wave and a complete absence of the rectoanal inhibitory reflex.

These data suggest that gut motility disorders in MEN type 2B are caused by inadequately organized autonomic nervous system activity that originates from hyperplasia of the enteric nervous system.