Plexiform neurofibroma

Case contributed by Dr Irvine Sihlahla


Soft tissue swelling which feels like a bag of worms on examination. Associated pain for 6 months but no constitutional symptoms

Patient Data

Age: 30 years
Gender: Male

Extensive fusiform dilation of peripheral nerves of both lower limbs with the lesion demonstrating T2W hypointense center with peripheral T2W hyperintense signal "target sign". No distal muscle atrophy or fat infiltration to indicate denervation atrophy.

Annotated image

The image shows the classic target sign associated with neurofibroma which is depicted as a central T2W hypointensity surrounded by T2W hyperintense signal.

Lower limbs


X-rays demonstrate extensive soft tissue swelling with no subcutaneous calcifications. There is associated smooth bone remodeling from compressive effects. No periosteal reaction or cortical destruction.

Case Discussion

The case illustrates plexiform neurofibroma in a patient with neurofibromatosis type 1. The neurofibroma demonstrates a characteristic target sign on T2W imaging. Patients with neurofibroma are followed up to exclude malignant degeneration. Neurofibromas are WHO grade 1 benign tumors.

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