Case reports: transient osteoporosis of the hip: an atypical case.

We present the case report of a 37 year-old woman who had transient osteoporosis in her third trimester of pregnancy. The condition spread beyond the hips and involved all six major joints of the lower limbs. The polyarticular involvement is the first to our knowledge. The condition resolved spontaneously in the usual manner during 12 months postpartum. The differential diagnosis is an important consideration, as investigation may be limited by concerns for the fetus. This includes regional migratory osteoporosis, inflammatory arthritis, septic arthritis, avascular necrosis, stress fracture of the femoral neck, synovial disorders, and neoplasia. We report the typical results and management of transient osteoporosis as a reminder of this uncommon, but impressive condition.