Neuroendocrine Cancer of Pancreas Presenting as Cushingʼs Syndrome: 2011 ACG Presidential Poster

Abstract

Purpose: A 59 year-old white woman with recently diagnosed HTN presented with new onset diabetes which was difficult to control. She also had hypokalemia, weakness, easy bruisability, and weight loss (30 lb in 6 months). Initial suspicion of Cushings Syndrome was confirmed with elevated 24 hour urine free cortisol. ACTH was also elevated. Cortisol was not suppressed with low or high high dose dexamethasone test, suggesting an ectopic ACTH Syndrome. CRH stimulation test failed to increase ACTH or cortisol which was consistent with diagnosis of ectopic ACTH Syndrome. CXR was negative for lung nodule. CT scans showed a heterogenous mass lesion involving the neck and proximal body of the pancreas, and a solitary metastatic lesion in liver segment. Octreotide scan showed hyperintense uptake in the same areas as the mass seen on CT Scans. FNA of the liver showed a neoplasm with neuroendocrine differentiation. Patient underwent distal pancreatectomy and right hepatic resection. Pathology of the resected tumor showed a large cell neuroendocrine carcinoma extending into peripancreatic soft tissue with perineuraland lymphovascular (Figure 1) invasion. Immunocytochemical stains showed tumor cells were strongly and diffusely positive for synaptophysin which is a marker of neuroendocrine tumor. Post surgery, patient did extremely well. Her diabetes and hypertension resolved over course of few months. Post surgical cortisol levels were within normal limits. Lung tumors cause more than half of the cases of ectopic ACTH syndrome. The most common forms of ACTH-producing tumors are small cell lung cancer, which accounts for about 13 percent of all lung cancer cases, and carcinoid tumors—small, slow-growing tumors that arise from hormone-producing cells in various parts of the body. Other less common types of tumors that can produce ACTH are thymomas, pancreatic endocrine tumors, and medullary carcinomas of the thyroid. Ectopic adrenocorticotropic hormone production by the pancreatic neuroendocrine tumor is relatively rare, and patients with this tumor show poor prognosis.Figure: No Caption available.