Metabolic Bone Disease in Pseudohypoparathyroidism: Radiologic Features

We reviewed the radiographs of six patients with pseudohypoparathyroidism (PHP) manifested by variable renal and skeletal resistance to parathyroid hormone (PTH). Features compatible with hyperparathyroid bone disease, osteomalacia, and rickets were observed. Skeletal changes of hyperparathyroidism included (a) subperiosteal bone resorption, (b) radiolucent lesions, caused by either brown tumors or bone cysts, (c) slipped capital femoral epiphyses, (d) focal areas of osteosclerosis, (e) periosteal neostosis, and (f) osteopenia with reduced cortical and trabecular bone volume. Histologic bone features were compatible with osteitis fibrosa in all patients, which suggests that the skeleton responded to the bone-remodeling effects of PTH despite hormonal resistance at other target sites. Skeletal changes of rickets included metaphyseal irregularities, cupping, and widening of the growth plates. Osteomalacia was indicated by Looser zones in one patient and confirmed by histologic evidence in three patients.