title: Hypophosphatemic osteomalacia: an unusual clinical presentation of multiple myeloma.
abstract: An unusual case of a 75-year-old man is presented who had multiple stress fractures due to adult onset hypophosphatemic osteomalacia, which was the result of Fanconi syndrome, with light chain cast proximal tubulopathy due to multiple myeloma. A 75-year-old man presented with diffuse pain and muscle weakness. He had multiple stress fractures, low serum phosphate, decreased renal tubular reabsorption of phosphate, and normal PTH and FGF23, indicating adult onset hypophosphatemic osteomalacia. Phosphate supplements with calcitriol resulted in clinical recovery and healing of stress fractures. Because of proteinuria, a renal biopsy was performed that revealed Fanconi syndrome with light chain cast proximal tubulopathy and light kappa chains were found in serum and urine. A bone biopsy confirmed the diagnosis of multiple myeloma, and treatment with chemotherapy resulted in cytological and clinical recovery.
authors.affiliation: University Hasselt, Diepenbeek, Belgium, margotreyskens@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Reyskens
authors.forename: K
authors.initials: K
authors.lastname: Sleurs
authors.forename: L
authors.initials: L
authors.lastname: Verresen
authors.forename: M
authors.initials: M
authors.lastname: Janssen
authors.forename: J
authors.initials: J
authors.lastname: van den Bergh
authors.forename: J
authors.initials: J
authors.lastname: van den Berg
authors.forename: P
authors.initials: P
authors.lastname: Geusens
mesh_terms: D000368:Aged; D002117:Calcitriol / Q000627:therapeutic use; D019587:Dietary Supplements; D005198:Fanconi Syndrome / Q000150:complications; D000089703:Fibroblast Growth Factor-23; D015775:Fractures, Stress / Q000209:etiology; D006801:Humans; D017674:Hypophosphatemia / Q000209:etiology*; D008297:Male; D009101:Multiple Myeloma / Q000150:complications* / Q000175:diagnosis; D010018:Osteomalacia / Q000188:drug therapy / Q000209:etiology*; D010710:Phosphates / Q000627:therapeutic use
chemical_list: C000717427:FGF23 protein, human; D010710:Phosphates; D000089703:Fibroblast Growth Factor-23; D002117:Calcitriol