Malignant peripheral nerve sheath tumors presenting as spinal dumbbell tumors: clinical outcomes and characteristic imaging features

Purpose: To investigate the clinical outcomes and imaging features of malignant peripheral nerve sheath tumors (MPNSTs) presenting as spinal dumbbell tumors. Methods: We retrospectively reviewed the clinical outcomes and imaging features of consecutive cases of spinal dumbbell MPNSTs (n = 8) and schwannomas (n = 15). Results: A maximal diameter >5 cm was more frequently seen in MPNSTs (88 %) than in schwannomas (14 %). Irregularly lobulated margins occurred frequently in MPNSTs (75 %), but not in schwannomas (21 %). Indistinguishable boundaries were observed in 63 % of MPNSTs, but only 7 % of schwannomas. Osteolytic bone destruction was found exclusively in MPNSTs (50 % of MPNSTs vs. 0 % of schwannomas). Conclusions: There is little clinical information relating to spinal dumbbell MPNSTs. We propose that the following imaging features are suggestive of spinal dumbbell MPNSTs: maximal diameter >5 cm, irregularly lobulated shape, boundary indistinguishable from surrounding tissues, and osteolytic bone destruction.