Case report

A 38-year-old woman gave a 2-year history of periodic left anterior thigh pain (figure 1), described as deep and excruciating. It would begin 2–3 days before menstruation. Its numerical rating scale score ranged from 5 to 7/10, rapidly peaked (up to 10/10), lasted 5–6 days and then vanished, with no pain between menses. She had seen various orthopaedic and pain medicine specialists, with a thorough radiological work-up, including lumbosacral MRI with gadolinium contrast (figure 2) and ultrasound scan and MR scan of the abdomen and pelvis, which were all normal. She was diagnosed elsewhere with psychogenic pain and treated with benzodiazepines, selective serotonin reuptake inhibitors and psychotherapy, with no effect.

She was referred for neurological consultation, which she considered ‘the last resort’, before stopping any further medical test or treatment and living with the pain that had ‘no organic cause but came from a wrong state of mind’. On examination, the left patellar reflex was decreased and the femoral nerve stretch test was mildly positive on the left. According to the neuropathic pain diagnostic algorithm, she had probable neuropathic pain (table …