traumatic neuroma

Traumatic neuromas may occur from acute or chronic injury to a nerve.

Clinical presentation

The patient presents with a focal area of pain and tenderness to palpation. There should be a history of injury (including iatrogenic injury, i.e. surgery) to the area. They may develop 1-12 months after nerve injury.

Pathology

A traumatic neuroma is not a neoplasm, but is formed from one of two main processes:

spindle neuroma: from a reactive fibroinflammatory disorganized regeneration around a nerve after an injury, such as traction injury or chronic repetitive stress (e.g. Morton neuroma)
terminal neuroma (such as "stump neuroma"): can occur after transection of the nerve (e.g. limb amputation, ilioinguinal pain post herniorrhaphy)

Radiographic features

Ultrasound

at the site of the patient's pain
- swollen nerve, occasionally mass-like (comparison with the opposite side is often helpful)
- hypoechoic
- loss of normal fibrillar pattern
- usually small, but can be as large as 5 cm
the parent nerve of some small nerve may be difficult or impossible to discern

MRI

fusiform swelling of a nerve or a bulbous mass at a nerve ending
- the parent nerve of some small nerves may be difficult or impossible to discern
T2/STIR
- inhomogeneous hyperintensity
- may have a hypointense rim
T1 C+ (Gd): variable contrast enhancement

Treatment and prognosis

Treatment varies according to local expertise but can range from excision, anesthetic injection, or alcohol ablation.