Marrow signal changes observed in follow-up whole-body MRI studies in children and young adults with neurofibromatosis type 1 treated with imatinib mesylate (Gleevec) for plexiform neurofibromas

We observed bone marrow signal changes (BMSC) in patients with plexiform neurofibromas after treatment with imatinib mesylate (Gleevec). To evaluate the pattern and natural history of BMSC. The data were obtained from a pilot study of imatinib mesylate in patients with plexiform neurofibromas. All patients underwent baseline and sequential whole-body STIR 1.5-T MRI after treatment. The bone marrow signal on MRI was evaluated for abnormalities, location and pattern, and any change on follow-up studies. The study group included 16 patients (8 males) with a median age of 14 years (range 4 to 25 years). The mean whole-body MRI follow-up duration was 1.9 years. Of the 16 patients, 14 (88%) developed BMSC. The signal change was asymmetrical in 9 of the 14 patients (64%). The appendicular skeleton was involved in all 14 patients and the axial skeleton in 3 patients (21%). BMSC was followed in 13 patients and decreased signal was seen in 9 patients (69%) after a mean duration of 1.3 years of treatment (range 0.6 to 2.9 years); no complications were observed. BMSC appeared in most patients with neurofibromatosis type 1 following treatment with imatinib mesylate. BMSC was unusually asymmetrical and involved the lower extremities. On follow-up, BMSC often showed a decrease without complications. (orig.)