Chronic ulnar nerve thickening with elbow mass: Imaging features suggestive of Hansen’s disease

Hansen’s disease remains an important and often under-recognized cause of peripheral neuropathy in endemic regions, particularly in the absence of cutaneous manifestations. Peripheral nerve involvement may occasionally present as a focal mass, closely mimicking neoplastic pathology and resulting in diagnostic delay. We report the case of a 16-year-old male migrant laborer who presented with a 4-year history of progressively enlarging swelling along the medial aspect of the left elbow, associated with weakness and wasting of the intrinsic muscles of the hand. Initial clinical suspicion was that of a benign peripheral nerve sheath tumor. Multimodality imaging revealed focal expansile thickening of the ulnar nerve with an associated encapsulated lesion demonstrating diffusion restriction, peripheral rim enhancement, internal debris, and calcifications, along with diffuse proximal ulnar nerve thickening and secondary denervation changes. Ultrasound confirmed continuity of the lesion with the ulnar nerve, while radiographs demonstrated soft-tissue swelling with amorphous calcifications. In the appropriate clinical, imaging, and epidemiological context, these findings were considered suggestive of Hansen’s disease with probable ulnar nerve abscess formation. The patient was referred to a higher center with a dedicated leprosy treatment unit. On telephonic follow-up, he reported being advised of inpatient admission and supervised initiation of multidrug therapy. Histopathological confirmation could not be obtained due to loss to follow-up. This case highlights the importance of recognizing the imaging spectrum of peripheral nerve involvement in Hansen’s disease and underscores the role of radiology in prompting diagnostic reconsideration of infectious neuropathies that may masquerade as peripheral nerve tumors.