RESUMEN
BACKGROUND: Right-side fixation of the sigmoid colon is a rare anatomical variant associated with intestinal malrotation (Choi et al. in J Korean Surg Soc. 84(4):256-60, 2013). Differently from other forms of malrotation, this variant has not been associated thus far with acute surgical conditions. CASE PRESENTATION: In this report, we present a 65-year-old Caucasian patient admitted for bowel obstruction symptoms. Computed tomography scan revealed right-side fixation of the sigmoid colon extended to the subhepatic recess complicated by obstructed internal herniation of the ileum. In this patient, the sigmoid colon occupied a recess posterior to the ascending colon and right Toldt's fascia. Within this narrow anatomical space, an ileal loop was trapped causing internal herniation with resultant close-bowel obstruction of both ileum and sigmoid colon. The ileal loop was released surgically and the anatomical abnormality corrected. CONCLUSIONS: To our knowledge, this is the first case of right-side fixation of the sigmoid colon causing acute obstruction secondary to internal herniation of the small intestine. Early recognition and precise anatomical definition of such anatomical variants are essential to optimize their surgical approach.