Coexisting Non-inflammatory Fibrotic Entrapment and Traumatic Neuroma as Distinct Mechanisms of Anterior Cutaneous...

Anterior cutaneous nerve entrapment syndrome (ACNES) is an important cause of focal abdominal wall pain and may be missed when routine imaging and laboratory findings are normal. We report an eight-year-old girl who developed sharp, well-localized right lower abdominal pain six months after bilateral laparoscopic percutaneous extraperitoneal closure (LPEC) for inguinal hernia. She was initially evaluated at a university hospital and diagnosed with irritable bowel syndrome; however, the pain progressed and prevented school attendance. On presentation to our department, she had a clear focal tender point to the right of the umbilicus with a positive Carnett sign, consistent with ACNES. One day before surgery, she additionally reported new localized pain at a pigmented lesion in the right groin, and a neurectomy was performed at two sites. At the periumbilical site, a cutaneous nerve was identified immediately beneath the skin incision and excised with the fascia. Pathology demonstrated fibrosis around the neurovascular bundle, thickened nerve fascicles, and close apposition of the nerve fascicles to an artery. At the right groin site, no cutaneous nerve was found directly beneath the skin; a cutaneous nerve branch extending cranially was identified on deeper exploration and excised with the fascia. Pathology demonstrated adipose scar formation and a perineural/fascial neuroma with whorled nerve fascicles intertwined with collagen fibers. Postoperatively, pain at both sites resolved promptly without recurrence. This case illustrates that distinct mechanisms of abdominal wall neuropathic pain, including ACNES and traumatic neuroma, may coexist after LPEC.