To describe a rare case of encephalomyelitis as a paraneoplastic neurologic syndrome (PNS) caused by a well-differentiated neuroendocrine tumor (WDNET) of the pancreas.

PNS are rare syndromes associated with high morbidity and mortality. While growing research in recent decades has allowed for more precise diagnostic criteria, PNS have heterogeneous phenotypes and further research is required to better define less common cancer associations.

A 63-year-old man with a history of hypertension and atrial fibrillation presented with 5 days of acute urinary retention and bilateral lower extremity weakness. The exam was notable for mild lower extremity weakness, increased bilateral patellar and achilles reflexes, dysarthria and a partial right CN VI palsy. Initial imaging showed a long-segment lesion in the thoracic cord extending from C6 through T11 and at L2 with mild enhancement as well as nerve root enhancement at L2 and L4. MRI brain showed enhancing lesions involving the pons, midbrain, posterior limbs of the internal capsules and bilateral middle cerebellar peduncles.

An extensive work-up was initiated and ruled out infectious and demyelinating causes. CSF studies revealed an opening pressure >50,  TNC count >1000, protein >200 and normal glucose. CT chest, abdomen, pelvis revealed a small pancreatic tail lesion and serum chromogranin A was elevated at 153. The patient’s exam declined precipitously despite high dose steroids and plasma exchange and within weeks nearly all brain stem reflexes were lost. While paraneoplastic serum and CSF panels were negative for a specific antibody, post-mortem autopsy concluded the cause of death was from complications of paraneoplastic encephalomyelitis in the setting of a pancreatic WDNET.

This case demonstrates that as PNS continue to be described, less common cancer associations may become more prevalent. Continued study of these rare syndromes is crucial to elucidate future clinical associations and further improve diagnostic accuracy and patient outcomes.