Endocrine Abstracts

Introduction: Glucagonoma is a rare pancreatic neuroendocrine functional tumor, with an estimated incidence of 1 in 20 million people. At the moment of diagnosis, the majority of patients present locoregional and liver metastases.

Case report: We present the case of a 46 years old male patient, diagnosed with glucagon secreting pancreatic neuroendocrine tumor in February 2018. As part of the glucagonoma syndrome, the patient was also suffering from insulin treated diabetes mellitus, necrolitic migratory erythema, deep venous thrombosis, iron deficiency anemia, hypoalbuminemia, diarrhea, weight loss, cheilitis, stomatitis. Furthermore, he presented glucocorticoid osteoporosis with left pertrochanterial fracture and vertebral fractures, because he was treated with methylprednisolon for the skin lesions initially diagnosed as disseminated pustular psoriasis. Serum glucagon=2138 pg/ml (NV<209), chromogranin A=462 μg/l (NV=27-94), and thoraco-abdomino-pelvic CT scan revealed 3.5/4.4 cm solid tumor located in the caudal part of the pancreas, with no visible metastases. The screening for MEN1 syndrome was negative. A somatostatin receptor-based imaging was not available. Endoscopic ultrasound with fine needle aspiration and biopsy were performed, confirming the diagnosis of well-differentiated neuroendocrine tumor (ki67=2%). Due to the increased surgical risk at that moment, the surgical intervention (distal pancreatectomy, peripancreatic lymph node dissection, en-bloc splenectomy) was postponed and treatment with somatostatin analogs (SSA) was initiated. Intravenous zolendronic acid was administered as treatment for osteoporosis. One month after initiating the SSA treatment, there was a significant clinical improvement, with remission of diarrhea and almost complete cure of skin lesions. Chromogranin A level was within the normal range. Bone scintigraphy revealed multiple spots with increased radiotracer uptake, suggestive for metastases, while the 18F-FDG PET-CT scan performed afterwards showed no signs of metastases. On the other hand, although the pancreatic tumor had a low proliferative index, PET-CT scan revealed very intense FDG uptake in this area, suggesting that, if present, the metastases would have been detected by this investigation. Since the therapeutic approach is different depending on the presence or absence of metastatic disease, octreoscan was recommended in order to decide if the patient would benefit from the tumor resection.

Conclusions: Due to its low incidence, the diagnosis of glucagonoma is very rarely taken into account. This case report emphasizes the importance of an early diagnosis, thus allowing initiation of treatment in the incipient stages of the disease. While the medical treatment with SSA usually lead to a significant clinical improvement, the surgical therapy is the only one that may allow complete disease remission.