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Radiologic Resolution of Malignant Infantile Osteopetrosis Skeletal Changes after Hematopoietic Stem Cell Transplantation
Methods: Twelve patients(8 male & 4 female, median age of 14.5 months) with proved MIOP underwent HSCT. Patients received transplant from relative matched donor(n=9), unrelated matched(n=1), unrelated mismatched cord blood(n=1) and HLA-haploidentical relative(n=1). The source of stem cell were bone marrow(n=7), peripheral blood(n=4) and cord blood(n=1). Baseline, 6th and 12th month post-HSCT whole body bone surveys were performed. All patients survived except one who died at 8 months due to infection.
Results: Baseline corticomedullary differentiation was not detectable in any patient, however by 6th month it was perceivable in 3(p-value: 0.25) and by 12th month in 9 patients(p-value: 0.004). Baseline endobone appearance was seen in long and flat bones of 11 and 12patients, respectively. Resolution of long bones endobone appearance was seen in 9patients by 6th month(p-value: 0.008). None of 11patients had endobone appearance by 12th month(p-value: 0.002), while flat bone endobone appearance was persistent in 10patients at 12th month. By 6th month, significant disappearance of rachitic changes in long bones was seen, however it was persistent in ribs in 11patients. By 12th month, there was not any evidence of rickets in ribs and long bones of any patient(P-values<0.005). Of all subjects with baseline skull base sclerosis, by 6th and 12th month it was persistent in 9(p-value: 0.25) and 5patients(p-value: 0.03) respectively. The mean metaphysical band to femur length ratio was significantly higher at 6th month compared to the baseline(7.56 ± 3.66 vs. 2.87 ± 1.25, p-value: 0.001)
Conclusion: This study demonstrated the resolution in skeletal changes of osteopetrosis after successful HSCT. Long bones rachitic changes and endobone impression were the first to resolve within 6 months after HSCT.