Reason: Please evaluate large intramuscular plexiform neurofibroma in left thigh; is it attached to a major nerve? History: young woman with NF1 who has developed a rapidly growing mass in left thigh Within the semitendinosus muscle of the left thigh, is a lobulated mass which demonstrates homogeneously low T1 signal and heterogeneously high T2 signal with intermediate T2 signal internally, consistent with an atypical peripheral nerve sheath tumor. The mass measures approximately 3.6 x 2.3 x 4.7 cm (transverse by AP by CC) and demonstrates heterogeneous enhancement. The lesion does not appear to originate from the major neurovascular bundle in the posterior thigh.A second presumed peripheral nerve sheath tumor is present adjacent to the right gluteal muscles, seen only on the AP coronal view, but is incompletely evaluated.
Peripheral nerve sheath tumor within the left semitendinosus muscle, which does not appear to originate from the major neurovascular bundle in the posterior thigh. However, atypical appearance on T2 and post gadolinium imaging raises concern for the possibility of a malignant nerve sheath tumor, and clinical correlation is advised.