A 43-year-old woman was admitted to our department to investigate a 6-month history of nocturnal cramps and pain in her left leg. She denied significant prior illness or medication use. The pain was intermittent, was exacerbated by a lying position, and radiated from the proximal posterior part of the left lower limb to the medial malleolus. Findings on neurological examination, including deep palpation of the posterior part of the left thigh, were unremarkable. Tinel sign was absent.