The Unique Case of Lumbar Dural Metastasis From Cervical Carcinoma on Pembrolizumab

Lumbar metastasis is a rare manifestation of cervical carcinoma which may present as lower extremities symptoms. Immune-checkpoint inhibitors like pembrolizumab, used for the treatment of various metastatic carcinomas, have been linked to Guillain-Barré Syndrome (GBS), which is characterized by ascending weakness and areflexia. A 52-year-old female with metastatic cervical cancer on pembrolizumab for two months presents with lower back pain, progressive bilateral lower extremities ascending weakness, and areflexia of affected limbs. Cerebrospinal fluid analysis showed albuminocytologic disassociation. Spine magnetic resonance imaging showed L4-L5 fracture associated with metastasis and contrast-enhancing adjacent dura and nerve roots. Despite the clinical presentation being consistent with lumbar metastasis, the possibility of masked pembrolizumab-induced GBS presented a therapeutic challenge. Plasmapheresis conferred no clinical improvement and later nerve conduction study was unrevealing for GBS. Subsequently, laminectomy of lumbar vertebrae improved the symptoms. The unique clinical scenario of lumbar dural metastasis from cervical cancer on pembrolizumab, a condition with a similar clinical presentation, is explored in this case.