200 Section - Brachial Plexitis Mimicking Cervical Radiculopathy: The True Culprit

Case Diagnosis: Brachial plexitis from compression by infraclavicular lipoma

Case Description: This case report describes a 52-year-old male with upper extremity pain and paresthesia, initially suspected to have cervical radiculopathy, but ultimately diagnosed with a large infraclavicular lipoma compressing the brachial plexus. Electrodiagnostic testing demonstrated chronic left C5/C6 radiculopathy with reinnervation potentials and without active denervation. Cervical radiographs showed degenerative changes throughout the cervical spine. MRI chest with and without contrast revealed a large non-enhancing mass measuring 6.0 x 8.3 x 11.7 cm in the left infraclavicular region, consistent with lipoma. There was downward displacement of the left brachial plexus adjacent to the subclavian artery.

Discussions: The diagnostic complexity in distinguishing brachial plexus compression by a mass lesion from cervical radiculopathy is well illustrated by this case. Both conditions can present with overlapping symptoms making clinical differentiation challenging, especially when physical findings are subtle or nonspecific. Electrodiagnostic studies may help localize the lesion but are not always definitive, particularly in chronic or multifocal disease. Failure to recognize a mass lesion such as a lipoma or tumor can lead to inappropriate management, including unnecessary spine interventions that do not address the underlying pathology and expose patients to procedural risks such as infection, nerve injury, and anesthesia-related complications. In cases where the mass is malignant, such as a peripheral nerve sheath tumor or metastasis, delays in diagnosis and definitive treatment may result in tumor progression, increased morbidity, and compromised oncologic outcomes.

Conclusions: Clinicians should consider brachial plexus lesions, such as compression by a lipoma, in patients with atypical or refractory upper limb symptoms, especially when physical findings suggest a mass or when initial workup for radiculopathy is inconclusive. Integration of clinical, electrodiagnostic, and advanced imaging findings is paramount for accurate diagnosis and management. Early recognition and appropriate referral are essential to prevent unnecessary procedures and optimize recovery.