Acquired vitamin D-resistant rickets caused by aggressive osteoblastoma in the pelvis: a case report with ten years' follow-up and review of the literature.

Rickets or osteomalacia secondary to tumor in either bone or soft tissue is rare and interesting in that it can be cured after removal of the tumor. The majority of the reported cases occurred in adults older than 30 years, and the most commonly associated types were vascular and fibrous tumors. We present a new case of aggressive osteoblastoma in the ilium, which induced vitamin D-resistant rickets in an 8-year, 9-month-old boy. Radiographs and blood chemistry findings on admission showed typical features of active hypophosphatemic ricketts. He underwent three local excisions of the tumor. At 10-year follow-up, the patient was symptom free but short. When a child has symptoms of rickets that develop relatively later than ordinary vitamin D-resistant rickets, every effort should be made to search out a tumorous lesion before attributing it to a renal origin.