Pancreatic tumor with hepatic metastases secreting vasoactive intestinal polypeptide: Treatment options and long-term follow-up results

INTRODUCTION: Vasoactive intestinal polypeptide secreting tumor (VIPoma) are rare neuroendocrine tumors (NETs) and there isn't any robust recommendation for management. In here, we present a metastatic VIPoma case which is managed by multidisciplinary approach. CLINICAL CASE: A 64-year-old male patient presented with profuse watery, bloodless and mucous diarrhea and weight loss. In the laboratories analyzes, creatinine:1.02 mg/dL, sodium:136 mmol/L, potassium:2.9 mmol/L, chlorine:115 mmol/L, phosphorus:1.4 mg/dL, calcium:9.8 mg/dL were detected. Infectious and inflammatory causes of diarrhea were excluded. In abdomen magnetic resonance imaging (MRI), there were a 25×23×33 mm lesion in the tail of the pancreas and multiple metastatic liver lesions. Metastatic liver lesion biopsy revealed a NET. Plasma VIP level was 199 ng/L (23–63). Multidisciplinary committee was decided to distal pancreatectomy and metastatic liver lesions’ chemoembolization (TACE). Octreotide LAR 20 mg/month was started. Distal pancreatectomy revealed a 35 mm, grade 1 NET. TACE was done for metastatic liver lesions. At the 3rd month follow-up, the patient's symptoms had improved and he had gained 6 kg. Metastatic liver lesions’ size reduced and plasma VIP level was detected <20 ng/L. At 18th months, abdominal MRI revealed progression of liver metastases. Multidisciplinary committee was decided to re-TACE and octreotide LAR dose increased to 30 mg. At the 3rd month follow-up, it was found that the size of the liver lesions decreased and the VIP level was <20 ng/L. One year later, progression of liver metastases was detected. Plasma VIP level was 168 ng/L. Ga-68 DOTA-TATE PET/CT showed increased uptake in metastatic liver lesions. Peptide receptor radionuclide therapy (PRRT) was decided by the multidisciplinary committee. The patient received 8 cycles of Lu-177 treatment. However, PET/CT control revealed a newly developed metastatic lesion in liver. During this period, the patient applied to the emergency department with the complaint of fever. Hgb: 8.1 g/dL, thrombocyte: 60.1 10^3/uL, WBC: 11.3 10^3/uL were found. A leukoerythroblastic picture was observed in the peripheral blood smear. In bone marrow aspiration biopsy, 3.28% blasts were detected. The patient was evaluated as MDS secondary to PRRT with current results. EPO treatment was started. Since the monocyte count remained above 1000 10^3/uL for more than 6 months during the follow-up of the patient, chronic myelomonocytic leukemia was accepted and azacitidine treatment was started. However, the patient died at the end of the first cycle due to sepsis. CONCLUSION: VIPomas are rare NETs with characteristic symptoms; however, they are often detected with unresectable metastatic disease. Therefore, it is important to keep NETs in mind when evaluating watery diarrhea. Due to the rarity of these tumors, there is no consensus to guide treatment. Therefore, multidisciplinary management of the disease will be more effective. [Figure: see text]