Differentiation between neurofibromas and malignant peripheral nerve sheath tumors in neurofibromatosis 1 evaluated by MRI

Abstract

MRI shows features which were helpful for differentiating MPNST from NF.

Multimodal Imaging in Neurofibromatosis Type 1-associated Nerve Sheath Tumors

“…3), which is frequently present particularly in the case of subcutaneous neurofibroma. This is characterized by a central hypointense area in an overall homogenous hyperintense spaceoccupying lesion in T2w, and is attributed to a central accumulation of dense collagen-rich stroma [31]. In rare cases, however, this can also be observed with MPNST [33] n/a n/a n/a n/a n/a n/a 0 % 13 % 0.53 unclear margins 68 % 33 % 0.03 n/a n/a n/a 38 % 3 % 0.007 77 % 32 % 0.04 intratumoral lobulation 63 % 17 % 0.007 n/a n/a n/a 50 % 12 % < 0.02 n/a n/a n/a .001 n/a n/a n/a intratumoral cystic changes 21 % 17 % 1 39 10 % 0.02 0 % 0 1 n/a n/a n/a peritumoral edema n/a n/a n/a 29 % 0 % 0.005 n/a n/a n/a 66 % 23 % 0.01 target sign 0 % 67 % < 0.0001 n/a n/a n/a 25 % 57 % 0.14 n/a n/a n/a MPNST -malignant peripheral nerve sheath tumors; BPNST -benign peripheral nerve sheath tumor; CE -contrast enhanced; 1 median broma, thus resulting in an addition of existing benign tumor mass and malignant tissue portions.…”

“…Furthermore, this is primarily a result, however, of the often late diagnosis. Poorly defined demarcation with surrounding tissue is another malignancy criterion [31,33,35]. However, this is likewise a relatively advanced sign of a malignant transformation, since in this case growth exceeding the capsule must be present, which -given the genesis of MPNST from plexiform neurofibromas -can be expected to appear late.…”

“…However, this is likewise a relatively advanced sign of a malignant transformation, since in this case growth exceeding the capsule must be present, which -given the genesis of MPNST from plexiform neurofibromas -can be expected to appear late. An intratumoral lobulation in T1w can be observed in many MPNST, but also for 12 -17 % of plexiform neurofibromas [31,33]. The lobulation apparently is rooted in the reticulated growth of the plexiform neurofibromas, which can involve multiple nerve fascicles and lead to a diffuse accumulation of densified nerves [22].…”

“…The lobulation apparently is rooted in the reticulated growth of the plexiform neurofibromas, which can involve multiple nerve fascicles and lead to a diffuse accumulation of densified nerves [22]. Another characteristic of MPNST is presentation of portions appearing hyperintense in T1w, which lead to an overall inhomogenous appearance of MPNST in T1w [31]. Histologically, this corresponds to intratumoral hemorrhagic areas [31].…”

“…In addition, criteria described in individual articles as being significantly associated with MPNST have not been reproducible in all studies. In some cases, characteristics ascribed to MPNST such as, for example, an irregular tumor shape were associated more with benign tumors in several studies [31,35]. A characteristic criterion of peripheral nerve sheath tumors is the presence of what is referred to as target sign ( • " Fig.…”