Pembrolizumab-induced Guillain-Barré syndrome in triple-negative breast cancer: A case report

The programmed cell death protein 1 inhibitor pembrolizumab has become a key treatment for various cancers, including triple-negative breast cancer. However, it is associated with immune-related adverse events, including rare but serious neurological complications such as Guillain-Barré syndrome (GBS). GBS is a potentially life-threatening autoimmune disorder characterized by muscle weakness and paralysis. We present a unique case of pembrolizumab-induced GBS to highlight the importance of recognizing this complication and managing it promptly in patients receiving immune checkpoint inhibitors.

A 69-year-old woman with a medical history of hypertension, anxiety, depression, and stage IIIB triple-negative breast cancer treated with pembrolizumab, carboplatin, and paclitaxel, presented to the emergency department with a 1-month history of tingling, lower extremity weakness, and shooting pain. Symptoms progressed to global weakness, ascending paralysis, and double vision. Neurological examination revealed significant lower extremity weakness and sensory deficits. Magnetic resonance imaging of the lumbar spine and cerebrospinal fluid analysis confirmed GBS. Initial treatment with intravenous immunoglobulin led to relapse, requiring additional intravenous immunoglobulin and high-dose glucocorticoids. The patient's condition improved, pembrolizumab therapy was permanently discontinued, and she was discharged to a rehabilitation facility.

Pembrolizumab can induce GBS, necessitating early recognition, prompt diagnosis, and multidisciplinary management to prevent serious complications.