1336 A Rare Case of a Non-Functioning Pancreatic Neuroendocrine Tumor

Abstract

INTRODUCTION: Pancreatic neuroendocrine tumors (PNETs) are very rare, representing 1–2% of all pancreatic tumors and 7% of all NETs. 85% of PNETs are non-functional PNETs (NF-PNETs). Most are found incidentally at an advanced stage because patients are asymptomatic and the tumors do not secrete hormones that would manifest with symptoms. We report a case of a 32-yr-old female diagnosed with widely metastatic intermediate grade NF-PNET. For pancreatic neuroendocrine tumors that have metastasized, prognosis is poor, with a survival of only 1–3 years. CASE DESCRIPTION/METHODS: A 32-yr-old female presented with increasing abdominal girth and lower extremity swelling. A CT of abdomen and pelvis showed a massively enlarged liver with diffuse metastases, pancreatic tail mass, vaginal and peritoneal masses, sigmoid colon mass, and gallbladder masses. Core biopsy of her liver showed a metastatic NF-PNET. Following 6 cycles of chemotherapy with capecitabine and temozolomide, repeat CT showed a significant decrease in her pancreatic mass and metastases. Her chromogranin A level decreased from 5800 to 35 ng/dL. Then she had an exploratory laparotomy, lysis of adhesions, and bilateral oopherectomy. Postoperatively she was changed to octeotide and everolimus until MRI showed a progression of her liver metastases. She was switched to 4 cycles of treatment with doxorubicin, 5-fluorouracil (5-FU), and streptozocin as well as Y90 to her liver. Repeat MRI showed stable disease in her liver. DISCUSSION: Based on histology and pathology Ki 67 of 40% and 10 mitoses/10 HPF our patient's tumor was classified as G2 intermediate grade. Our patient had none of the potential risk factors for PNETs. Imaging includes an Octreoscan, negative for our patient, and CT scans in 3 phases. Our patient tested negative for increased levels of all hormones and biomarkers seen with newly diagnosed NETs. Serum levels of CgA are elevated in the 80-90% of patients with advanced NETs and can be used to monitor disease progression and treatment as seen in our case. Surgery is the only treatment proven to prolong survival as seen with our patient. Medical treatment with somatostatin analog octreotide plus chemotherapy regimen of doxorubicin, 5-FU and streptozocin are used for locally advanced and metastatic pancreatic endocrine carcinomas like with our case. This case is important because it illustrates an atypical presentation in a younger patient and it is important for practitioners to be vigilant in diagnosing rare diseases.