ODP296 An unusual presentation of Glucagonoma syndrome.

INTRODUCTION: Glucagonoma is an uncommon neoplasm of the pancreatic neuroendocrine islet α-cells. At least 50% of cases will have metastatic disease when diagnosed. Glucagonomas can be associated with other tumors in Multiple Endocrine Neoplasia syndrome 1 (MEN 1), but this association is rare and comprises no more than 3% of glucagonomas. Glucagonoma syndrome is a rare paraneoplastic phenomenon characterized by necrolytic migratory erythema (NME), hyperglucagonemia, diabetes mellitus, anemia, weight loss, glossitis, cheilitis, steatorrhea, diarrhea, and venous thrombosis. CASE PRESENTATION: A 55-year-old Caucasian woman was admitted for acute onset of shortness of breath and she was seen by endocrinology team for persistent hyperglycemia. Her medical history revealed a long-standing uncontrolled type 2 diabetes mellitus and an episode of left lower extremity deep-vein thrombosis. Her physical exam revealed tachycardia, otherwise unremarkable, with no skin lesions. Laboratory results showed hyperglycemia (387 mg/dl), Hemoglobin A1C, 9%, and hypoalbuminemia (3.4 g/dl). Her Hemoglobin (13 g/dl), white cell count (6100/μL), and platelet level (19.3 × 104/μL) were within normal limits. The patient underwent CT pulmonary angiogram, which showed a large saddle pulmonary embolism as well as a distal pancreatic mass measuring 4.5×3.4 cm, which contains numerous coarse calcifications. Pancreatic mass was confirmed in a CT abdomen and pelvis with contrast. CA 19-9 was elevated to 51 U/ml (normal range, 0- 35U/ml). The GI team performed an Endoscopic Ultrasound, and samples were sent for FNA and flow cytometry which revealed a 4 cm irregular heterogeneous mass with calcifications at the distal pancreatic body, positive for Pankeratin (CK), Cam 5.2, Synaptophysin, Chromogranin A, and CD56, consistent with Pancreatic neuroendocrine Tumor. Her serum glucagon level was elevated to 447 pg/mL (normal range, 50 -150 pg/mL), while her levels of other hormones, such as somatostatin or gastrin, were within normal limits. Glucagonoma of the pancreas was diagnosed, and a spleen-preserving distal pancreatectomy was performed. Histopathological examination revealed a 5.9 cm alpha-cell pancreatic tumor without lymphovascular or perineural tumor invasion. (AJCC 8th edition staging II, pT3, pN0, MX, G1). Immunohistochemical staining was strongly positive for glucagon. A gallium-68 positron emission tomography (68Ga-PET, Netspot) did not show metastasis. Post resection surveillance showed normalization in Glucagon level and no evidence of recurrence in CT abdomen. CONCLUSION: The diagnosis of glucagonoma is often delayed due to unusual initial manifestations of glucagonoma. Early diagnosis provides a good chance of complete surgical removal as the only curative treatment. Presentation: No date and time listed