Plexiform neurofibroma

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.

Clinical presentation

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.

Radiographic features


Non specific infiltrative subcutaneous lesion.


Reported signal characteristics include:

  • T1: hypointense
  • T2: hyperintense +/- hypointense central focus (target sign)
  • T1 C+: mild enhancement

Differential diagnosis

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.

See also

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