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.

ABSTRACT

BACKGROUND: We observed bone marrow signal changes (BMSC) in patients with plexiform neurofibromas after treatment with imatinib mesylate (Gleevec). OBJECTIVE: To evaluate the pattern and natural history of BMSC. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.