Segmental Absence of Intestinal Musculature in Adults: A Report of Five Cases Among 86 Intestinal Perforations

Among 86 adult patients who underwent surgery for intestinal perforation, excluding cases caused by cancer invasion or appendicitis, diverticulitis (33/86, 38%) was identified as the most common cause of perforation, followed by ischaemia (7/86, 8%) and segmental absence of intestinal musculature (SAIM) (5/86, 6%). In patients with SAIM-related perforation, the site of perforation was the sigmoid colon in four cases and the caecum in one. SAIM-related perforation occurred predominantly in older women and most frequently involved the sigmoid colon. The four patients with sigmoid colon perforation showed an abrupt loss of the muscularis propria. In the patient with caecal perforation, the muscularis propria exhibited separation and thinning with focal complete loss. Secondary inflammation or haemorrhage associated with the perforation was observed in the bowel wall surrounding the perforation site. However, there was no evidence of primary suppurative inflammation or necrosis causing of perforation. Given that the prevalence of SAIM among patients with bowel perforation appeared to be higher than previously assumed, it is essential to histologically examine sufficient tissue samples to avoid missing this diagnosis. Recognition of SAIM is clinically important, especially in adults without previous or current evidence of intestinal disease, as it should be considered a possible cause of intestinal perforation, thereby facilitating early diagnosis and prompt treatment.