Plexiform neurofibroma is a benign tumor of peripheral nerves (WHO grade I) arising from a proliferation of all neural elements, pathognomonic of neurofibromatosis type 1 (NF1). It involves single or multiple nerve fascicles that arises from major nerve branches.
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Clinically, it presents as a subcutaneous mass which feels like a "bag of worms". Most of the time, it is a superficial cutaneous/subcutaneous lesion, but it can occur almost anywhere in the body. Symptoms may be related to local mass effect.
It is found in approximately 30% of patients with neurofibromatosis type 1. There is a risk of malignant transformation in 5-10% of cases.
Non specific infiltrative subcutaneous lesion.
Reported signal characteristics include:
- T1: hypointense
- T2: hyperintense +/- hypointense central focus (target sign)
- T1 C+: mild enhancement
- plexiform schwannoma
- lymphatic malformation
- venous malformation
History and etymology
The term plexiform comes from the infiltrative growth pattern that, histologically, looks like a plexus or a network. It is typically associated with tumors of neural derivation. Plexiform neurofibromas are considered the prototype of the plexiform pattern 1.
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