Femoral neuropathy in a patient with rheumatoid arthritis.

Femoral mononeuropathy (FMN) as an extraarticular finding of rheumatoid arthritis (RA) is a phenomenon which has not been reported previously. We report a 53-year-old female patient with RA, presenting FMN findings during the course of the disease. On examination, right quadriceps and iliopsoas muscles showed grade 3 weakness on the Medical Research Council (MRC) scale. Sensory examination revealed sensory loss in the right medial leg and thigh. Patellar tendon reflex was absent in the right side. A diagnosis of a partial right femoral neuropathy was confirmed using nerve conduction study and electromyography. The probable mechanism of FMN was thought to be vasculitis.