Diarrhea after
liver transplantation is a common complication.
Vasoactive intestinal peptide-producing tumor (
VIPoma) is a rare cause of watery
diarrhea; 80% of such
tumors occur in the pancreas, but it is rare in liver. Hypersecretion of
vasoactive intestinal polypeptide can stimulate intestinal water and
electrolyte secretion, and patients with
VIPoma present with watery
diarrhea,
hypokalemia, and
dehydration. Here we report on a 50-year-old man who presented with a 7-month history of watery
diarrhea. He had undergone an orthotopic split-
liver transplantation for
hepatocellular carcinoma in November 2011. Two months after the
liver transplantation, he presented with watery
diarrhea,
dehydration, and
hypokalemia.
Antibiotics, immunosuppressive drugs modification,
antidiarrheal agents,
antispasmodics, adsorbents, and fasting were alternately used to control the
diarrhea, but his symptoms remained unchanged. A
chromogranin examination, a marker of pancreatic neuroendocrine
neoplasm, was positive in the third month of the
diarrhea history and
VIPoma was considered. Treatment with
somatostatin immediately controlled the
diarrhea, but the primary lesion could not be identified even after corresponding examinations were completed. In the ninth month of
diarrhea, a 1 × 1-cm lesion was detected in the right liver by ultrasonography.
Radiofrequency ablation was performed, and the
diarrhea stopped. Seventeen months later, the
chromogranin level decreased to normal and the patient was asymptomatic. Neither the recipient sharing the other liver portion nor the donor presented with any symptoms, so we wondered how the
tumor occurred. It is possible that a small
VIPoma lesion existed in the liver donor before the
transplantation, and that the immunosuppressive drugs induced
tumor development.