S3359 Adult Isolated Hypoganglionosis in the Anorectal Canal

Abstract

INTRODUCTION: Hirschsprung's disease (HD) is a congenital bowel innervation disorder characterized by the absence of ganglion cells in myenteric and submucosal plexus in the distal. The term ‘‘Variant HD’’ has been used to describe a heterogeneous group of intestinal innervation disorders with clinical presentation that resembles HD despite the presence of ganglionic cells seen on rectal biopsy. Isolated hypoganglionosis is a rare entity that present with persistent bowel symptoms similar to those with classical HD, however has resected bowel histopathological findings of reduced number of nerve cells in the myenteric ganglia. CASE DESCRIPTION/METHODS: We present a case report of a 19-year-old male who was diagnosed with isolated hypoganglionosis following a long history of fecal impaction and constipation since childhood. Patient presented to our institution with complaints of distended abdomen at 19 years of age. CT imaging demonstrated a massively distended rectosigmoid colon filled with abundant fecal material (Figure 1). An abdominal series revealed stool scattered throughout his colon and a dilated, saccular appearing rectum. A water soluble contrast enema exhibited a short segment (approximately 8 cm) narrowing of bowel in the region of the rectum with dilated upstream sigmoid colon (Figure 2). The remainder of the visualized bowel including proximal sigmoid, descending, transverse, ascending colon and cecum were of normal caliber. This imaging pattern was compatible with Hirschsprung's disease. The patient then underwent a laparoscopic-assisted proctosigmoidectomy with a stapled end to end coloanal anastomosis and a diverting loop ileostomy. Though the surgical pathology demonstrated the presence of ganglion cells in the sigmoid colon and rectum, the anorectal canal showed presence of rare ganglion cells (Figure 3). On follow up, the patient underwent another water soluble contrast enema that confirmed an intact anastomosis and he subsequently underwent successful ileostomy closure two months later. One week after closure, the patient had recovered well, reporting daily bowel movements with good evacuation control and no fecal incontinence. DISCUSSION: To our knowledge, this is the first case of adult HD variant, isolated hypoganglionosis, with histology demonstrating hypoganglionosis in the anorectal canal and no evidence of agangliosis in the rectum and sigmoid colon. Following removal of the remnant hypoganglionic intestinal segment, our patient’s bowel motility significantly improved.Figure 1.: Routine CT abdomen and pelvis with intravenous and oral contrast was performed on admission with axial images and coronal reformations (A and B, respectively). These images demonstrated marked sigmoid colonic fecal loading and dilation (white arrows), compatible with a chronic obstructive process such as Hirschsprung's disease.Figure 2.: Water soluble enema study was performed. (A) This study showed a short segment (8 cm) narrowing of the distal rectum (solid white arrow) with upstream dilatation of the proximal rectum (dashed white arrow). (B) The AP view demonstrates massive upstream dilation of the rectum and sigmoid colon.Figure 3.: H&E stain of anorectal canal (A) and sigmoid rectal area (B). Arrows indicate ganglion cells, which were rare in the anorectal canal region. Inserts show the higher magnification of the circled area. Bar = 50 um.