Calvarial doughnut lesions associated with high-turnover osteoporosis presenting in childhood

Osteogenesis imperfecta and juvenile osteoporosis are two well-described sy ndromes of osteoporosis presenting in childhood. There are also several ref erences in the radiology literature to calvarial doughnut lesions (CDLs), a reas of radiolucency surrounded by a dense and well-defined area of sclerot ic bone, either as an incidental finding or associated with childhood fract ure. We have characterized the metabolic abnormalities in a 13-yr-old boy w ith CDLs and multiple fractures and followed him during his progression thr ough puberty. The patient's paternal grandmother; father; and paternal aunt , uncle, and first cousin were similarly affected, and a mandibular lesion in the uncle was pathologically described as fibrous dysplasia. The subject 's physical examination was significant for bony protuberances of the skull and normal hearing, sclearal hue, dentition, and joint flexibility. Radiog raphs revealed calvarial CDLs and osteopenia which was confirmed by bone mi neral density (BMD) testing. Biochemical markers of bone formation and reso rption were elevated compared to normal adult and a transiliac crest bone b iopsy confirmed high-turnover osteoporosis. Over 6 yr, with no specific the rapy, BMD gradually normalized, but the CDLs increased in size, bone turnov er remained elevated by biochemical markers, and he continued to fracture. The subject's affected father and maternal grandmother had normal BMD and n o history of adult fracture. CDLs with high-turnover osteoporosis should be considered in the differential diagnosis of pediatric osteoporosis. During puberty the BRID normalizes but the high-turnover state persists, and the propensity to fracture eventually decreases in older affected adults. The C DLs may be a variant of fibrous dysplasia, and further study is necessary i n order to elucidate the stimulus for increased bone turnover and the famil ial nature of this syndrome.