Unusual paraneoplastic neurological syndrome secondary to a well differentiated pancreatic neuroendocrine tumor: a case report and review of the literature

BACKGROUND: Paraneoplastic neurological syndrome (PNS) is a heterogeneous group of disorders affecting any part of the nervous system, in a patient affected by cancer. PNS is estimated to occur in 0.01 to 8 % of cancer patients, with higher incidence in those with small cell lung cancer, gynecological tumours or hematological disease. Paraneoplastic cerebellar degeneration (PCD) is the most common PNS, but it has never been reported in patients with pancreatic well-differentiated neuroendocrine tumours. CASE PRESENTATION: A 61-year-old man presented with an unusual PNS and absence of circulating neural auto-antibodies. Subsequently, contrast-enhanced computed tomography revealed a large pancreatic mass, together with multiple liver metastases, histologically diagnosed as a well-differentiated neuroendocrine tumor. Initial treatment with long-acting somatostatin analogue (octreotide LAR) and prednisone achieved a biochemical response (reduction of chromogranin A level) and a radiological disease control, but patient experienced only a brief improvement of neurological symptoms. Seven months after the onset of the symptoms, he died from neurological impairment. CONCLUSIONS: PNS can be associated with metastatic non-functioning well-differentiated pancreatic neuroendocrine tumors. These tumors may be unresponsive to treatment with somatostatin analogues and an early neurological treatment should be considered for the optimal management of these uncommon cases.