Windswept Deformity: A Rare Skeletal Manifestation in an Adolescent with Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT) in adolescents is rare and has severe manifestations as compared to adults. Skeletal involvement in primary hyperparathyroidism in the form of deformities like genu valgus, genu varus and cubitus varus is rare and limited to case reports and case series. There is only one case of genu varus with genu valgus on the contralateral extremity (windswept deformity) that has been reported to date in the literature. We report the case of a 19-year-old male who presented with isolated progressive bending of his legs at the knee (windswept deformity) for three years. He was found to have hypercalcemia, hypophosphatemia, high alkaline phosphatase, high intact parathyroid hormone (iPTH), normal 25-hydroxy vitamin D level and a normal kidney function test. A diagnosis of primary hyperparathyroidism was made. On imaging studies, a left inferior parathyroid adenoma was localized and was successfully removed surgically. Serum calcium and iPTH normalized post-operatively. The patient is being planned for corrective osteotomy after stabilization of alkaline phosphatase levels.