VIPomas: an update in diagnosis and management in a series of 11 patients

VIPoma is a rare pancreatic endocrine tumor (PET) which secretes excessive amounts of VIP (Vasoactive Intestinal Peptide) that causes a special clinical syndrome characterized by secretory diarrhea, hypokalemia and achlorhydria. Among a total number of 76 patients (pts) with PETs, we present in this study 11 pts with VIPoma syndrome focusing on our diagnostic and therapeutic approach, in parallel with a brief review of the literature.

Eleven pts (7 males and 4 females), aged from 2 to 83 years (mean age 53.1 years) were included. The diagnosis was based upon compatible clinical features and serum VIP values and was supported by the estimation of other peptides and neuroendocrine markers such as gastrin, pancreatic polypeptide and chromogranin-A (CgA). In 10/11 pts, diagnosis was confirmed histopathologically. The primary or metastatic lesions were located by conventional imaging methods or by OCTREOSCAN or Endoscopic Ultrasound (EUS). The follow-up period ranged from 2.5-13.5 years (mean 4.8 years).

Chronic secretory diarrhea, which persisted despite fasting, was the main symptom in all pts of our study. VIP levels at the time of diagnosis were more than 3 or 10 times the upper normal limit in 7/11 (63.6%) or 4/11 (36.4%) pts, respectively. The primary lesion was detected by CT scan or MRI in 6/11 (54.5%), with EUS or abdominal angiography in 4/11 (36.4%). OCTREOSCAN revealed a solitary lesion in the right hepatic lobe, not detected by all the previous studies, while it detected, as a whole, the primary lesion in 10/11 (91%), and the metastases in 3/4 (75%) pts. In 7/11 (63.6%) the primary lesion was located in the pancreas, whereas in the rest it was in the duodenum or retroperitoneum. A surgical resection was possible in 7/11 (63.6%) pts, while pts with metastatic disease already or poorly differentiated tumors also received additional treatment with somatostatin analogues and chemotherapy. Liver metastases and poor differentiation of tumors seemed to be negative prognostic factors.

Clinical suspicion, early diagnosis and precise management may affect survival and improve the quality of life of patients. Also, surgical treatment, as extensive as possible, in combination with somatostatin analogues or chemotherapy when necessary, may also result in prolonged survival, also in patients with advanced disease.