Sacless Spigelian hernia: a rare diagnostic and operative challenge—a case report

Spigelian hernia is a rare ventral abdominal wall hernia occurring through a defect in the Spigelian aponeurosis along the semilunar line, accounting for 1%–2% of all abdominal wall hernias, with a high risk of incarceration due to its narrow and rigid fascial neck. A sacless variant, in which only preperitoneal fat protrudes without a peritoneal sac, is exceptionally rare and poses a diagnostic challenge. A 52-year-old male presented with a reducible left lower abdominal swelling and intermittent pain. Diagnostic laparoscopy showed intact peritoneum with no visible hernia defect. A strong clinical suspicion precluded conversion to open exploration, revealing a 2 × 3 cm defect in the Spigelian aponeurosis containing preperitoneal lipomatous tissue without a peritoneal sac. A preperitoneal mesh repair was undertaken. Sacless Spigelian hernia being extremely rare, a high index of suspicion and readiness for open exploration are essential when imaging and laparoscopy are inconclusive.