J Med Cases

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

Article copyright, the authors; Journal compilation copyright, J Med Cases and Elmer Press Inc

Journal website https://www.journalmc.org

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

Table 1. Timeline

March 13, 2013

Admission to the emergency department (ED) of our hospital with acute diarrhea and severe hypokalemia

March 19, 2013

Diagnosis of tumor in the pancreatic tail with abdominal MRI

March 20, 2013

Transfer of the patient to the Endocrinology Department of the collaborating oncology hospital

March 22, 2013

Distal pancreatectomy with splenectomy

March 22, 2013

Transfer to the intensive care unit (ICU) after surgical resection of the tumor

March 28, 2013

Discharge from ICU and transfer to the Department of Surgery of the collaborating oncology hospital

April 3, 2013

Hospital discharge of the patient from the oncology hospital

April 10, 2013

Admission 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, 2013

Transfer of the patient to the Department of Surgery of the collaborating oncology hospital

April 15 - 16, 2013

Emergent esophagogastroduodenoscopy due to relapse of melena. Possible foci of hemorrhage from the major duodenal papilla (hemosuccus pancreaticus)

April 20, 2013

Drainage of retroperitoneal cystic lesion

April 26, 2013

Discharge from the Department of Surgery of the oncology hospital

May 17, 2013

First clinical follow-up of the patient at the Endocrinology Department and Department of Surgery of the oncology hospital. Patient stable with no symptoms.

June 2013

Second follow-up with abdominal magnetic resonance imaging (MRI), endocrine assessment and specific tumor markers

November 2013

Follow-up with triple-phase abdominal CT

January 2014

Follow-up with biochemical and specific tumor markers

June 2014

Follow-up with specific tumor markers and abdominal CT

October 2014

Octreotide scan negative for relapse of the disease or metastasis

2015 - 2023

Yearly 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 presentation	At seventh day	Normal range
Hemoglobin (g/dL)/hematocrit (%)	17.2/44.6	15.1/40.6	(11.5 - 15.5 g/dL)/(37-47%)
Potassium (mEq/L)	2.1	2.2	3.5 - 5.1 mEq/L
Calcium (mg/dL)	11.1	12.2	8.5 - 10.5 mg/dL
Sodium (mEq/L)	123	129	135 - 147 mEq/L
Chloride (mEq/L)	89	100	96 - 108 mEq/L
Magnesium (mg/dL)	2.6	2.4	1.8 - 2.4 mg/dL
Phosphorus (mg/dL)	2.4	2.4	2.5 - 5 mg/dL
Glucose (mg/dL)	159	108	70 - 110 mg/dL
Urea (mg/dL)	221	50	12 - 42 mg/dL
Creatinine (mg/dL)	4.2	0.7	0.6 - 1 mg/dL
Albumin (g/dL)	4.7	3.3	3.5 - 5 g/dL
C-reactive protein (mg/dL)	0.21	3.2	< 0.5 mg/dL
pH of arterial blood sample	7.25	7.31	7.35 - 7.45
Potassium in 24-h urine sample (mmol/24 h)	-	7.20	25 - 100 mmol/24 h

Table 2. Laboratory Results of the Patient

At presentation

At seventh day

Normal range

Hemoglobin (g/dL)/hematocrit (%)

17.2/44.6

15.1/40.6

(11.5 - 15.5 g/dL)/(37-47%)

Potassium (mEq/L)

2.1

2.2

3.5 - 5.1 mEq/L

Calcium (mg/dL)

11.1

12.2

8.5 - 10.5 mg/dL

Sodium (mEq/L)

123

129

135 - 147 mEq/L

Chloride (mEq/L)

100

96 - 108 mEq/L

Magnesium (mg/dL)

2.6

2.4

1.8 - 2.4 mg/dL

Phosphorus (mg/dL)

2.4

2.5 - 5 mg/dL

Glucose (mg/dL)

159

108

70 - 110 mg/dL

Urea (mg/dL)

221

12 - 42 mg/dL

Creatinine (mg/dL)

4.2

0.7

0.6 - 1 mg/dL

Albumin (g/dL)

4.7

3.3

3.5 - 5 g/dL

C-reactive protein (mg/dL)

0.21

3.2

< 0.5 mg/dL

pH of arterial blood sample

7.25

7.31

7.35 - 7.45

Potassium in 24-h urine sample (mmol/24 h)

7.20

25 - 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 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 marker	Laboratory values	Normal range
Carcinoembryonic antigen (ng/mL)	0.97	< 5.1 ng/mL
Calcitonin (pg/mL)	759.2	< 10 pg/mL
Chromogranin A (ng/mL)	360.9	19.4 - 98.1 ng/mL
Neuron-specific enolase (ng/mL)	0.47	< 12.5 ng/mL
Intact parathormone (pg/mL)	12	10 - 65 pg/mL
Thyroid-stimulating hormone (µIU/mL)	1.28	0.30 - 4.0 µIU/mL
Free thyroxine (pg/mL)	11.38	7.8 - 19.4 pg/mL
Adrenocorticotropic hormone (pg/mL)	44.91	10 - 60 pg/mL
Morning cortisol (µg/dL)	50.07	6.2 - 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

Table 4. Specific Laboratory Investigations in the Endocrinology Department

Blood marker

Laboratory values

Normal range

Carcinoembryonic antigen (ng/mL)

0.97

< 5.1 ng/mL

Calcitonin (pg/mL)

759.2

< 10 pg/mL

Chromogranin A (ng/mL)

360.9

19.4 - 98.1 ng/mL

Neuron-specific enolase (ng/mL)

0.47

< 12.5 ng/mL

Intact parathormone (pg/mL)

10 - 65 pg/mL

Thyroid-stimulating hormone (µIU/mL)

1.28

0.30 - 4.0 µIU/mL

Free thyroxine (pg/mL)

11.38

7.8 - 19.4 pg/mL

Adrenocorticotropic hormone (pg/mL)

44.91

10 - 60 pg/mL

Morning cortisol (µg/dL)

50.07

6.2 - 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