Diagnostic Ultrasound - Abdomen and Pelvis

Pancreatic Neuroendocrine Tumor
Diagnoses: Pancreas
TERMINOLOGY
• Historical terms: Islet cell tumor; carcinoid
IMAGING
• Well-differentiated, circumscribed mass(es) in pancreas
without pancreatic ductal dilation
• Functioning tumors: Small, round, hypervascular mass
• Nonfunctioning: Large, well-demarcated, lobulated mass
with heterogeneous enhancement pattern
○ Small areas of cystic change/necrosis and calcification
○ Displaces, rather than invades, adjacent structures
TOP DIFFERENTIAL DIAGNOSES
• Mucinous cystic pancreatic neoplasm
• Solid pseudopapillary neoplasm
• Pancreatic ductal carcinoma
• Pancreatic metastases or lymphoma
• Serous cystadenoma of pancreas
KEY FACTS
PATHOLOGY
• All pETs have malignant potential
• ↑ serum chromogranin A is 70% sensitive for pETs
CLINICAL ISSUES
• Most occur sporadically
• Familial syndromes: Multiple endocrine neoplasia type I;
von Hippel-Lindau , neurofibromatosis type I, tuberous
sclerosis
• Nonfunctional tumors: Usually asymptomatic but large
size at time of diagnosis may cause mass effect and
abdominal pain
• Functional tumors present with syndromes, commonly
○ Whipple triad, Zollinger-Ellison
• Prognosis: Best for insulinomas
○ 50-80% noninsulinomas recur or metastasize
○ Poor prognostic features: size > 2-4 cm; cystic change,
calcification, necrosis
• Surgical resection is only curative treatment for pETs
(Left) Graphic demonstrates a
well-circumscribed, round,
solid mass in the
pancreatic body with regional
metastatic lymphadenopathy
ſt. (Right) Transabdominal
ultrasound demonstrates a
well-defined, hypoechoic
pancreatic mass ſt to the
right of the superior
mesenteric vein st.
(Left) Transverse
intraoperative ultrasound
demonstrates a round,
hypoechoic, solid-appearing
mass with through
transmission ſt in the body of
the pancreas. (Courtesy A.
Kamaya, MD.) (Right)
Corresponding intraoperative
color Doppler ultrasound
demonstrates internal flow ſt
within the solid mass.
(Courtesy A. Kamaya, MD.)
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