412 - Adjacent Spindle and Stump Neuroma: A Case Report

As the median nerve descends the arm, it gives off branches to muscles enabling forearm flexion, wrist flexion, and finger movement. Electromyography (EMG) and ultrasound are two commonly used diagnostic modalities for neuropathy in the upper extremities and used together can diagnose neuromuscular disorders. 


Case Description:

53-year-old male with history of distal humerus fracture following a gunshot wound (GSW) status-post surgical fixation presented with weakness and reduced sensation. Exam showed reduced sensation, most pronounced in the median and radial distribution and had weakness in anterior interosseous nerve muscles and ulnar innervated muscles. EMG demonstrated active and severe median sensorimotor neuropathy and sensory ulnar neuropathy.  Sonographic evaluation of the median nerve demonstrated a trifid nerve at the wrist and a partially transected median nerve with a distal stump neuroma and a spindle neuroma at the medial epicondyle. The GSW led to a partial transection where the intact portion created a classic spindle neuroma, and the transected portion created the classic stump neuroma.


Discussions: When observing both a stump neuroma and a spindle neuroma on the same nerve, distinct pathologies are evident. A stump neuroma typically arises after nerve transection. In this case, the proximal end of the severed nerve formed a bulbous mass due to nerve tissue attempting to reconnect or attach itself to nearby structures. Conversely, a spindle neuroma occurs when a nerve trunk sustains injury but remains anatomically intact. This injury leads to a localized area of swelling along the nerve, characterized by a homogeneous and hypoechoic appearance on imaging studies. Despite the swelling, the nerve fibers themselves remain undamaged, distinguishing it from a stump neuroma.

Conclusions: The coexistence of these two types of neuromas adjacently on the same nerve suggests an atypical nerve injury and distinct healing process. Understanding EMG and neuromuscular ultrasound is crucial in the diagnosis of this interesting case.