A Rare Case of Meralgia Paresthetica: Lateral Femoral Cutaneous Nerve Schwannoma Mimicking Appendicitis

Abstract

Meralgia paresthetica (MP) is a mononeuropathy caused by compression of the lateral femoral cutaneous nerve (LFCN), producing pain, numbness, and paresthesia over the anterolateral thigh. While MP is commonly due to benign compressive or metabolic causes, it may rarely result from structural lesions such as LFCN schwannomas. We report a 50-year-old woman with a one-month history of right lower quadrant abdominal pain and anterolateral thigh numbness, followed by cramping pain extending into the right leg. She also described a burning sensation in both soles. Examination revealed right iliac fossa tenderness with a positive psoas sign and sensory loss over the anterolateral thigh. Initially, a diagnosis of retrocecal appendicitis was considered. The straight leg raising test was negative, but leg elevation reproduced pain in the right iliac fossa, and neurodynamic testing (LFCN stretch test) reproduced pain over the lateral thigh. Imaging showed a dumbbell-shaped lesion along the right psoas muscle. Laparoscopy confirmed a multilobulated mass in direct continuity with the LFCN, which was completely excised, and the nerve was preserved. Histopathology confirmed a benign schwannoma with degenerative changes. At one month's follow-up, her abdominal pain had resolved, and thigh numbness had improved, though bilateral sole burning persisted and remained unexplained. This case highlights LFCN schwannoma as a rare structural cause of MP that can mimic chronic appendicitis, and it underscores the need to consider structural causes in refractory or atypical thigh pain with abdominal symptoms. It is also important to use imaging and histopathology for timely diagnosis and surgical management.