Megadose methylprednisolone treatment for malignant osteopetrosis

Long-term follow-up of two children with a variant of mild autosomal recessive osteopetrosis undergoing bone marrow transplantation

Malignant autosomal recessive (AR) osteopetrosis represents an absolute indication for bone marrow transplantation (BMT). Over the last 15 years, almost 100 BMTs for osteopetrosis have been reported. The median age at transplant of most patients is 4 months. Very few cases of mild AR osteopetrosis have been described. Here, we report the good outcome of two cases of mild AR osteopetrosis with a follow-up of 5 and 6 years, respectively, after an HLA-identical sibling transplant undergone at 5 and 12 years of age, respectively. At the time of BMT, severe visual impairment was present in both children. Bone biopsy demonstrated hypermineralization with virtual obliteration of the medullary spaces, rare microfoci of hematopoiesis and marked deficiency in osteoclastic activity. Successful engraftment was complicated by hypercalcemia, controlled by a combination of bisphosphonate, phosphate infusions, vigorous hydration and calcitonin. Following BMT, radiological and histological findings showed extensive bone resorption with marked augmentation of the osteoclasts in normalized marrow. No improvement was observed in visual acuity, despite complete remodeling of skeletal abnormalities. We conclude that allogeneic BMT is the only chance of curing mild AR osteopetrosis.

Osteopetrosis--improvement of hematologic findings with age

A three months old girl was admitted to the hospital for evaluation of pallor and abdominal distension. There was anemia, thrombocytopenia and extramedullary hematopoiesis. In the long bone roentgenogram medullary areas could not be distinguished and bone densities were increased. The patient was diagnosed for osteopetrosis with these findings and prednisolone treatment was begun and then discontinued since it was not effective. In the follow up, the need for blood transfusions decreased and then disappeared. We present a case which was diagnosed as osteopetrosis and followed up by blood transfusions and of which hematologic findings improved with age.