Large tumor of iliac bone in a young woman imitating malignant disease as a sign of primary hyperparathyroidism

Abstract

Detection of a bone tumor in a young adult draws suspicion of neoplastic disease.

A 22-year-old female was admitted for a bone tumor biopsy. MRI of the pelvis showed an osteolytic lesion at the level of the left sacroiliac joint. Radiologist suggested differential diagnosis between aneurysmal bone cyst and giant cell tumor of bone. Considering the high serum calcium and numerous foci of increased accumulation of the radioisotope on the bone scan, serum iPTH level was evaluated. The diagnosis of hyperparathyroidism was established. Neck ultra­sound revealed focal lesion corresponding to an enlarged parathyroid gland. Parathyroidectomy was performed. The iliac bone tumor showed to be a brown tumor of primary hyperparathyroidism, detected only rarely in adolescents.

Non-specific symptoms and lack of routine control of serum calcium in youths make an early diagnosis difficult; moreover, pathological features of brown tumor and giant cell tumor of bone are very similar.