BONE-MARROW SCINTIGRAPHY WITH TC-99M ANTI-NCA-95 TO MONITOR THERAPY IN MALIGNANT OSTEOPETROSIS

We report a case of a 2-mo-old girl with malignant osteopetrosis. Conv entional radiological investigations of the skull and left hand showed the characteristic pattern of generalized sclerosis. Bone marrow immu noscintigraphy with Tc-99m-labeled antibodies against nonspecific cros s-reactive antigen (NCA) 95 was performed before and after bone marrow transplantation. Before transplantation, whole-body images showed bon e marrow stores exclusively in the base of the skull. The rest of the skeleton did not reveal any hematopoietic activity. The liver and sple en showed increased antibody uptake as expected in extramedullary hema topoiesis. Repeat scintigraphy after bone marrow transplantation from her haploidentical father demonstrated an almost completely normalized tracer distribution corresponding to her clinical and hematological i mprovement. Bone marrow immunoscintigraphy appears to be an ideal comp lement to radiograph diagnostics in malignant osteopetrosis. In primar y diagnosis, scintigraphy demonstrates the quantitative extent of bone marrow displacement. It also proves an ideal tool in monitoring the e ffectiveness of therapy after bone marrow transplantation.