Acute abdominal pain due to sigmoid volvulus with persistent descending mesocolon: a case report

BACKGROUND: Persistent descending mesocolon, an anomaly of fixation of the mesentery of the descending colon, can sometimes cause complications such as intestinal obstruction and intussusception. We present the first reported case of sigmoid volvulus with persistent descending mesocolon. CASE PRESENTATION: An 82-year-old Japanese man had intermittent lower abdominal pain. Abdominal computed tomography showed dilation and a shift to the right side of the sigmoid colon, but no findings of volvulus. The next day, he presented continuous lower abdominal pain with bloody stool. A second abdominal computed tomography showed strangulation and dilation of the sigmoid colon, with shift from the right side of the abdominal cavity to the pelvic space. This suggested the descending colon was running to the medial side with sigmoid volvulus. Emergency surgery was performed for volvulus with persistent descending mesocolon. Operative findings revealed dilation of the sigmoid colon with a partial poorly colored region and strangulation that caused volvulus. After releasing the strangulation of the sigmoid colon, the descending colon was revealed to be running more to the medial side, with adherence to small intestinal mesentery. There was no Toldt’s fusion fascia at the descending colon. Persistent descending mesocolon was therefore diagnosed due to abnormality of fixation of the descending colon. The sigmoid colon, including the poorly colored region, was resected and reconstructed, while the inferior mesenteric and left colonic arteries were preserved because of the complexity of the vascular system running around the descending and sigmoid colon due to the shortened mesentery. These findings were pathologically compatible with circulatory compromise and intestinal degeneration due to sigmoid volvulus. The patient had no complications after discharge, including in relation to defecation. CONCLUSION: Persistent descending mesocolon can occasionally cause acute abdominal symptoms requiring immediate treatment. A computed tomography finding of the descending colon running more to the medial side than ordinary cases can aid diagnosis of persistent descending mesocolon.