The Journal of the Arkansas Medical Society Med Journal Sept 2019 FInal 2 | Page 10

SCIENTIFIC ARTICLE
Neuroendocrine Tumor: Presenting as a Case of Intractable Nausea
Naga S. Addepally, MD; Mohit Girotra; Benjamin Tharian, MD
Division of Gastroenterology and Hepatology, UAMS Department of Medicine
Keywords
Neuroendocrine tumor, nausea
Introduction
T
he term neuroendocrine tumor is
referring to a group of cells that
secrete hormones in response to
neural or chemical stimuli. These cells are
widely distributed throughout the mucosa of the GI
tract and secrete a variety of hormones that lead to
varied clinical presentation and symptoms. Initially,
it was thought that these cells are derived from
neural crest cells, but they are now believed to be
derived from local multipotent stem cells 2 . There
are at least 13 different types of neuroendocrine
cells known to be present, which secrete a variety
of hormones in response to various stimuli. They
contain secretory granules in the cytoplasm,
which stain positive for Chromogranin A (CgA),
synaptophysin, neuron-specific enolase, and CD-
56. 2 Typical symptoms are related to the hormones
secreted. Back in 1907, when little was known
about neuroendocrine tumors, these tumors were
thought to be benign, and the word carcinoid
was coined by Oberndorf. 3 However, with more
knowledge about these tumors and their malignant
potential, the word carcinoid is obsolete and WHO
Image 1: Liver involved by metastatic
neuroendocrine tumor composed of
small cords and nodules.
has changed the nomenclature. The word GEP
NET (gastroenteropancreatic) is now being used
to address NETs originating from the GI tract
(GNET) and Pancreatic NET (PNET) for the NETs
arising from pancreas. The incidence of GEP NET
is increasing: 2.5 to 5 cases per 100,000, with
incidences as high as 8.4/100000 in autopsies. 4,15,16
However, the number might just be a low estimate
of the actual incidence as majority of tumors are
asymptomatic and are missed. 15,16 Incidence of
GNET is much higher than PNET. While most of
the cases are sporadic, NETs are associated with
familial endocrine cancers such as MEN, NF, VHL
syndrome. 17 A population-based study conducted
in 2004 showed the distribution of these tumors to
be highest in the small intestine (44%), followed by
the rectum (19.6%), appendix (16.7%), colon, and
stomach. The study also showed that GNET are
more common in females and African American. 17
Case presentation
A 33-year-old Caucasian woman with a
history of learning difficulty and seizure disorder
was referred for workup of a possible pancreatic
mass seen on CT scan. She had a 10-month history
of nausea and RUQ pain with fatty meals. No
other associated symptoms including fever, chills,
vomiting, altered bowel habits, hematemesis,
melena, weight loss, or rash. PSH is significant for
appendectomy in her childhood. Physical exam
was unremarkable including abdominal exam,
which showed non-tender abdomen, without any
signs of acute abdomen and good bowel sounds
were present in all quadrants. Lab work was
negative including liver function tests, lipase, and
amylase. Ultrasound and CT scan of the abdomen
showed cholelithiasis and a multilobulated mass
in the right paramedian aspect of the abdomen,
adjacent to duodenum and closely associated
with pancreas. It was unclear whether the mass
was arising from pancreas vs. duodenum vs.
adrenal vs. retroperitoneal from the cross sectional
imaging. Tumor markers including AFP, CA-19,
58 • THE JOURNAL OF THE ARKANSAS MEDICAL SOCIETY
Image 2: 40x image of well-differentiated
neuroendocrine tumor, involving the
duodenum, showing focal nucleoli along
with typical “salt and pepper” nuclei
spread throughout.
CEA and adrenal markers including ACTH, cortisol,
aldosterone, and metanephrines were normal.
Endoscopic Ultrasound (EUS) evaluation showed
8 x 8 cm heterogenous-appearing mass arising
from duodenal wall distinct from pancreas and
right kidney. Fine needle aspiration showed grade
I well-differentiated neuroendocrine tumor positive
for pan-CK, synaptophysin, and chromogranin.
CDX2 staining was positive, confirming the
gastrointestinal origin. Laparotomy showed a
large mass arising from second portion of the
duodenum and densely adhered to duodenum,
head of pancreas, and a second mass adhered to
the root of mesentery. There was also a metastatic
lesion to segment VI of the liver and antrum.
Whipple procedure (pancreaticoduodenectomy)
with wedge resection of the liver segment was
performed. Biopsy of the mass and the liver lesion
was consistent with well-differentiated grade 2
neuroendocrine tumor.
Discussion
The term carcinoid is now obsolete,
and is replaced by the more descriptive
terminology, neuroendocrine tumors (NET). The
gastroenteropancreatic NET (GEP-NET), incidence
of which is increasing (2.5 to 5 cases per
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