Segmental absence of intestinal musculature increasingly recognized in premature infants with perforated viscus: A case series

Introduction

Segmental absence of intestinal musculature (SAIM) is a pathological diagnosis, denoting focal absence of the muscularis propria in the presence of intact surrounding structures. This condition often presents as spontaneous intestinal perforation (SIP) and can be difficult to distinguish clinically from necrotizing enterocolitis (NEC).

Case presentations

We present 5 cases of premature babies with gestational age ranging from 24 + 3 weeks up to 32 + 1 weeks, who all presented with intestinal perforation before the 15th day of life. Three patients presented with a distended abdomen and discoloration and were subsequently found to have pneumoperitoneum on abdominal x-ray (AXR). The 2 other patients presented with clinical deterioration but without signs of intestinal perforation and were subsequently found to have pneumoperitoneum on AXR. All underwent bowel resection of perforated bowel with either ileostomy with mucous fistula or primary end-to-end anastomosis. Two patients required repeat exploratory laparotomies within a week of their initial surgery due to pneumoperitoneum in subsequent AXR caused by new perforations in other parts of the small bowel. One patient sustained an iatrogenic liver injury intra-operatively and passed away 1 day post-operatively. All patients were found to have SAIM on histopathological examination.

Conclusion

SAIM is a pathological diagnosis that can manifest as SIP and may denote a risk for recurrent peritonitis in premature infants who underwent bowel resection for perforated viscus without a clear etiology.