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.