Traumatic neuroma is a reactive process of exuberant proliferation of nerve endings in response to trauma or surgery. In a severed or injured nerve, the orderly growth of axons from the proximal to the distal stump during the healing phase reestablishes continuity. This process cannot take place if the proximal and distal stumps are not approximated or if there is no distal stump. In this situation, haphazard proliferation of Schwann cells at the proximal stump gives rise to a neuroma.
Traumatic neuromas can develop following surgery (amputations, cholecystectomy), trauma, and following autoamputation in utero of supernumerary digits. Some cases are associated with arteriovenous aneurysm, human bite, and deep burns. They present as painful or tender firm nodule near the proximal stump of the injured nerve. Grossly, they are circumscribed with a whitish-gray appearance. They consist of disorganized proliferation of nerve fascicles, Schwann cells, and fibroblasts embedded within the scar tissue adjacent to the cut ends of the nerve. The differential diagnosis includes neurofibroma and palisaded encapsulated neuroma.
Traumatic neuromas can be prevented by reapposing the ends of a severed nerve. Once a traumatic neuroma is formed, it should be removed by simple excision.