Isolated intestinal neuronal dysplasia- type B of ileum: A rare occurrence.

Intestinal neuronal dysplasia type B in the gastrointestinal tract is a rare occurrence and may occur alone or in combination with Hirschsprung disease. Distal colon seems to be a frequent site for isolated IND-B cases; however, small bowel involvement is scarcely reported. We report a case of 9 years old boy presenting with features of intestinal pseudo-obstruction for 5 years. Exploratory laparotomy revealed narrowed distal ileum with huge proximal dilatation. Histopathology of the resected terminal ileum revealed giant submucosal ganglion, hyperplastic submucosal nerves, and ectopic ganglion cells in the lamina propria suggestive of IND-B. Although IND-B involving ileum in isolation is a rare occurrence, suspicion should be kept in cases of intestinal obstruction with minimal response to conventional treatment.


Background
Intestinal neuronal dysplasia type-B (IND-B) is a rare congenital malformation of gastrointestinal innervation caused by dysplastic embryonal development of the enteric nervous system. The changes associated with IND-B are more common in the distal colon; however, they can affect any segment of the enteric nervous system and occur in different age groups ranging from newborns to adult, alone or in combination with Hirschsprung disease (HD) (1). Very rarely isolated ileal involvement has been reported (2). We herewith report a case of IND-type B in the ileum of a child presenting as chronic intestinal pseudo-obstruction (CIP).

Case Presentation
A 9 years old boy presented with intermittent abdominal pain and fullness sensation since 4 years of age. He had history of poor bowel habits with encopresis. Antenatal and natal histories were uneventful.
Histories of delayed passage of meconium, recurrent vomiting, retentive posturing or blood in stool were absent. Child had 2-3 episodes of febrile seizure which remitted on its own. He had received empirical anti-tubercular therapy for duration of 11 months for the presenting complaint, although there were no other systemic symptoms. There was no signi cant family history.
On general examination child's weight was 24.8 kg (3rd-10th centile), height 138 cm (10th − 50th centile) with failure to thrive. There was no pallor, icterus, edema or lymphadenopathy. On abdominal examination, inspection revealed distended abdomen with few prominent veins and visible peristalsis and borborygmi was present. There was no organomegaly on palpation. On per-rectal examination, there were no ssures, tags or gush of air and soft stool was palpable. Cardiovascular, respiratory and neurological examination showed no abnormalities.
On upper gastrointestinal endoscopy, oesophagus and stomach were normal. X-ray abdomen, erect posture, showed dilated small bowel loops with multiple air uid levels. Computed tomography of abdomen showed collapsed proximal jejunum and terminal ileum with dilated lower small bowel loops ( Fig. 1). Patient was evaluated for pseudo-obstruction. Exploratory laparotomy revealed narrowed distal ileum (approximately 15 cm) with huge proximal dilatation. Differential diagnosis of intestinal pseudoobstruction, hirschsprung disease and celiac disease were kept. Resection of distal ileum, cecum and appendix measuring 13 cm in length with end to end ileo-ascending colon anastomosis was performed. No apparent dilatation of the segment was noted. Histopathology of the terminal ileum revealed giant submucosal ganglion (average 10-14 ganglion cells per ganglion), hyperplastic submucosal nerves and ectopic ganglion cells in the lamina propria. Muscularis propria was largely unremarkable however, serosal fat revealed hypertrophic nerve bers. Histopathology was suggestive of IND-B (Fig. 2). Cecum and appendix were unremarkable.
On follow-up at one month, bowel prolapse from distal stoma site was noted. An exploratory laparotomy revealed proximal 20 cm of ileum anastomosed to ascending colon was hugely dilated. Another ileal resection was done till the normal calibre was identi ed with ileo-ascending colon reanastomosis.
Histopathology of the dilated part showed similar ndings. At 2 months follow-up, child is now gaining weight and passing formed stools.

Discussion And Conclusions
The patient presented with history of CIP. On laparotomy narrowed distal ileum with proximal dilatation was present. Histopathology revealed intestinal neuronal dysplasia-type B of ileum. Similar ndings were also present in the ileal segment found dilated and non-functional during second surgery.