A rare case of metastatic brachial plexopathy as an initial presentation of recurrent breast cancer mimicking shoulder disorder and peripheral nerve entrapment - A case report.

Background: The clinical manifestations of metastatic brachial plexopathy include pain, sensory loss, paresthesia, weakness, and reduced range of motion. These symptoms closely resemble those of shoulder disorders and peripheral nerve entrapment, which are commonly diagnosed in pain clinics, increasing the risk of misdiagnosis or delayed diagnosis, particularly in patients with a history of malignancy.

Case: A 51-year-old woman with a history of breast cancer in complete remission for 19 years presented with shoulder pain, arm weakness, and tingling in the fingers. Initial treatments for suspected cervical radiculopathy, shoulder disorders, and nerve entrapment were ineffective. Electromyography and nerve conduction studies revealed electrophysiological abnormalities consistent with left brachial plexopathy. Magnetic resonance imaging of the brachial plexus confirmed metastatic involvement. The patient is currently undergoing chemotherapy.

Conclusions: Clinicians must be vigilant of the possibility of malignancy in patients with a history of cancer and should pursue comprehensive diagnostic evaluations to exclude cancer recurrence.