A neuroma is a disorganized overgrowth of nerve tissue arising at the point of a nerve injury. This can occur after a missed or untreated nerve injury or after any amputation.
When nerves are divided, they attempt to heal and regrow. If a nerve is repaired the nerve can regenerate but if the regenerating nerve endings have nowhere to go, a disorganized ball of nerve fibres can form.
Neuromas are usually very painful, with pressure on them resulting in pain not just at that point but radiating to the normal target of the nerve. In neuromas in amputation stumps this gives rise to the experience of ‘phantom pain’ in a digit or limb that is no longer present.
A workup will involve some imaging to locate and examine the size of the neuroma, either with ultrasound or MRI. Nerve conduction testing is sometimes useful to determine the residual nerve function after an injury.
A combination of clinical examination and interpretation of the imaging together form the basis of diagnosis of a neuroma.