An Interesting Endoscopic Description of Borderline Ischemia in Sigmoid Volvulus: The "Fallen Leaves in Autumn" Sign.

Sigmoid volvulus (SV) is an uncommon cause of intestinal obstruction resulting from axial twisting of the sigmoid colon around its mesenteric base. In the absence of complications, endoscopic detorsion is considered the first-line treatment, whereas urgent surgery is required in cases of perforation, peritonitis, or failed detorsion (1). The "coffee bean sign" (massively dilated sigmoid loop directed to the right upper quadrant) and the "whirl sign" (twisting of mesentery and vessels) are well-established radiological findings of SV (2). By contrast, endoscopic features are less well characterized, and evaluating mucosal ischemia or necrosis endoscopically remains challenging. Completely black mucosa is indicative of full-thickness necrosis, while borderline ischemia may present with variably discolored mucosa, including yellowish and reddish spots. In 2021, Uysal et al. described this finding as the "fallen leaves in autumn" sign, reflecting superficial necrosis with preserved viability of deeper layers.   We report the case of an 83-year-old male admitted to the emergency department with abdominal pain and rectal bleeding. Imaging revealed classic signs of SV (Figure 1). During endoscopic detorsion, findings consistent with borderline ischemia were noted: loss of submucosal vascularity and scattered reddish-yellowish dots, some confluent. Areas suspected of complete necrosis displayed black mucosa with a sandpaper-like appearance (Figure 2). The patient underwent surgery for irreversible ischemia (Figure 3) but unfortunately died a few days later due to postoperative complications.   This case highlights that the "fallen leaves in autumn" sign may serve as a useful endoscopic descriptor of borderline ischemia in SV, complementing established radiological features.