A Rare Case of Hypophosphataemic Osteomalacia in von Recklinghausen Neurofibromatosis.

Background: Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is a one of the more common hereditary autosomal disorders. However, osteomalacia in neurofibromatosis type 1 is very rare tumour-induced osteomalacia; fibroblast growth factor-23 is usually implicated.

Patients And Methods: We report the case of a patient with a history of von Recklinghausen neurofibromatosis who presented with hypophosphataemic osteomalacia.

Results: The patient was treated with high-dose calcitriol and oral phosphate with clinical improvement.

Conclusion: Even though it is a rare entity, we must consider the diagnosis of hypophosphataemic osteomalacia in patients with neurofibromatosis in order to deliver appropriate treatment.

Learning Points: Osteomalacia during von Recklinghausen disease is a rare presentation of an uncommon condition and has a poorly understood mechanism.The treatment of oncogenic osteomalacia includes tumour removal which, however, is not always possible.Administration of calcitriol alone is not sufficient and phosphorus intake is mandatory to improve symptoms.