Journal of Medical Cases, ISSN 1923-4155 print, 1923-4163 online, Open Access
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Case Report

Volume 14, Number 9-10, October 2023, pages 307-316

Pancreatic Vasoactive Intestinal Peptide-Producing Tumor as a Rare Cause of Acute Diarrhea and Severe Hypokalemia


Figure 1.
Figure 1. The lesion (6.3 × 5.1 cm) is located in the anatomic position of the pancreatic tail (yellow arrows) and presents intermediate signal intensity relative to pancreas. (a) Axial T2 and (b) coronal T2 magnetic resonance images.
Figure 2.
Figure 2. (a) Unenhanced axial T1 magnetic resonance image depicting the lesion in the pancreatic tail (yellow arrows) with mildly hypointense signal relative to pancreas (motion artifacts are present). (b) Axial T1 image after intravenous contrast medium administration showing heterogeneous uptake in the lesion with central necrosis (yellow arrows).
Figure 3.
Figure 3. Transverse non-contrast computed tomography image that shows hypodense lesion (9 × 9 cm) in the anatomic position of the pancreatic tail (yellow arrows), which has been attributed to postoperative complication (lymphocele).


Table 1. Timeline
March 13, 2013Admission to the emergency department (ED) of our hospital with acute diarrhea and severe hypokalemia
March 19, 2013Diagnosis of tumor in the pancreatic tail with abdominal MRI
March 20, 2013Transfer of the patient to the Endocrinology Department of the collaborating oncology hospital
March 22, 2013Distal pancreatectomy with splenectomy
March 22, 2013Transfer to the intensive care unit (ICU) after surgical resection of the tumor
March 28, 2013Discharge from ICU and transfer to the Department of Surgery of the collaborating oncology hospital
April 3, 2013Hospital discharge of the patient from the oncology hospital
April 10, 2013Admission to the ED of our hospital with melena. Emergent esophagogastroduodenoscopy with endoscopic hemostasis of duodenal ulcer lesions. Computed tomography (CT) finding of cystic fluid collection in the retroperitoneal space.
April 11, 2013Transfer of the patient to the Department of Surgery of the collaborating oncology hospital
April 15 - 16, 2013Emergent esophagogastroduodenoscopy due to relapse of melena. Possible foci of hemorrhage from the major duodenal papilla (hemosuccus pancreaticus)
April 20, 2013Drainage of retroperitoneal cystic lesion
April 26, 2013Discharge from the Department of Surgery of the oncology hospital
May 17, 2013First clinical follow-up of the patient at the Endocrinology Department and Department of Surgery of the oncology hospital. Patient stable with no symptoms.
June 2013Second follow-up with abdominal magnetic resonance imaging (MRI), endocrine assessment and specific tumor markers
November 2013Follow-up with triple-phase abdominal CT
January 2014Follow-up with biochemical and specific tumor markers
June 2014Follow-up with specific tumor markers and abdominal CT
October 2014Octreotide scan negative for relapse of the disease or metastasis
2015 - 2023Yearly follow-up with clinical, biochemical, endocrine and imaging reassessment of the patient. No signs of relapse of the disease or metastasis


Table 2. Laboratory Results of the Patient
At presentationAt seventh dayNormal range
Hemoglobin (g/dL)/hematocrit (%)17.2/44.615.1/40.6(11.5 - 15.5 g/dL)/(37-47%)
Potassium (mEq/L) - 5.1 mEq/L
Calcium (mg/dL) - 10.5 mg/dL
Sodium (mEq/L)123129135 - 147 mEq/L
Chloride (mEq/L)8910096 - 108 mEq/L
Magnesium (mg/dL) - 2.4 mg/dL
Phosphorus (mg/dL) - 5 mg/dL
Glucose (mg/dL)15910870 - 110 mg/dL
Urea (mg/dL)2215012 - 42 mg/dL
Creatinine (mg/dL) - 1 mg/dL
Albumin (g/dL) - 5 g/dL
C-reactive protein (mg/dL)0.213.2< 0.5 mg/dL
pH of arterial blood sample7.257.317.35 - 7.45
Potassium in 24-h urine sample (mmol/24 h)-7.2025 - 100 mmol/24 h


Table 3. Differential Diagnosis of Acute Diarrhea
Infectious causes
  Viruses: Rotavirus, Norovirus, Adenovirus, Cytomegalovirus
  Bacteria: E. coli, Salmonella, Shigella dysenteriae, Campylobacter jejuni, Clostridium difficile, Yersinia, Vibrio cholerae
  Parasites: Giardia intestinalis, Cryptosporidium parvum, Entamoeba histolytica
Non-infectious causes
  Gastrointestinal causes: Inflammatory bowel disease, diverticulitis, ischemic colitis, short bowel syndrome, irritable bowel syndrome, etc.
  Endocrinopathies: Hyperthyroidism, adrenal insufficiency, carcinoid tumors, etc.
  Adverse effects of medications: Antibiotics, colchicine, antiarrhythmics, chemotherapeutic agents, etc.
  Dietary causes: Food intolerance or food allergies
  Malignancy: Colon cancer, intestinal lymphoma, etc.
  Iatrogenic causes: Radiation therapy, gastrointestinal contrast agents, etc.


Table 4. Specific Laboratory Investigations in the Endocrinology Department
Blood markerLaboratory valuesNormal range
Carcinoembryonic antigen (ng/mL)0.97< 5.1 ng/mL
Calcitonin (pg/mL)759.2< 10 pg/mL
Chromogranin A (ng/mL)360.919.4 - 98.1 ng/mL
Neuron-specific enolase (ng/mL)0.47< 12.5 ng/mL
Intact parathormone (pg/mL)1210 - 65 pg/mL
Thyroid-stimulating hormone (µIU/mL)1.280.30 - 4.0 µIU/mL
Free thyroxine (pg/mL)11.387.8 - 19.4 pg/mL
Adrenocorticotropic hormone (pg/mL)44.9110 - 60 pg/mL
Morning cortisol (µg/dL)50.076.2 - 19.4 µg/dL
24-h urine hydroxyindoleacetic acid (mg/24 h)9.6< 15 mg/24 h
Vasoactive intestinal peptide (pmol/L)> 120< 30 pmol/L