Mixed-sclerosing-bone-dystrophy: 42-year follow-up of a case reported as osteopetrosis.

We present a detailed metabolic investigation and 42-year radiological follow-up of a 52-year-old man with mixed-sclerosing-bone-dystrophy, the rare occurrence of two or more distinct patterns of sclerosing-bone-dysplasia (e.g., osteopathia striata, osteopoikilosis, melorheostosis) in a single subject. Review of radiographs from 1942, when he was reported to have osteopetrosis, demonstrated diffuse osteosclerosis, osteopathia striata, osteopoikilosis, and focal cortical hyperostosis. Forty-two years later, there had been significant progression and evolution of his skeletal disease with the appearance of new areas of osteopathia striata and osteopoikilosis and a generalized increase in skeletal mass as assessed radiographically. Presence of subperiosteal bone apposition on biopsy of the iliac crest together with chronic mild hypocalcemia, secondary hyperparathyroidism, and hypophosphatemia suggested that enhanced bone formation, perhaps with defective skeletal resorption, is a fundamental abnormality which accounts for the increased bone mass of this patient.