Diagnostic ultrasound ( PDFDrive )

CHAPTER 7 The Pancreas 251
FIG. 7.87 Lung Carcinoma Metastasis to Pancreas. Longitudinal
sonogram shows typical hypoechoic metastasis (arrow). Pancreatic
metastases are the most common pancreatic neoplasm in autopsy series
but are rarely found clinically because they generally occur late with
widespread metastatic disease.
FIG. 7.88 Renal Cell Carcinoma Metastasis to Pancreas. Longitudinal
color Doppler sonogram shows hypervascular metastasis. Differentiation
from a hypervascular pancreatic endocrine tumor may be dificult in
these cases.
of blood vessels, amount and thickness of connective tissue stroma,
number of ibrous septae that separate fat lobules, and amount
of water content in the fat. 192,194
Metastatic Tumors
In autopsy series, metastasis is the most common pancreatic
neoplasm, found about four times as oten as pancreatic cancer. 191
Clinical discovery of metastasis was rare until the advent of
modern imaging. 195 Pancreatic metastases are rarely clinically
signiicant because they generally occur late in patients with
widespread metastatic disease. Primary tumors that most oten
metastasize to the pancreas include renal cell carcinoma, breast
carcinoma, lung carcinoma (Fig. 7.87), melanoma, colon
carcinoma, and stomach carcinoma. 120,191,195
With metastasis to the pancreas, there may be a long interval
between initial diagnosis of the primary lesion and discovery of
the metastasis. his is especially true of renal cell carcinoma
and, to a lesser degree, melanoma. Klein et al. 195 found that the
mean delay between discovery of the primary renal cell carcinoma
and metastasis was 10 years; the longest interval was more than
24 years. A classic scenario is the discovery of a hypervascular
mass (or masses) in the pancreas of a patient who had a remote,
presumably cured renal cell carcinoma (Fig. 7.88). Diferential
diagnosis from a hypervascular pancreatic endocrine tumor may
be diicult in such cases.
CONTRAST-ENHANCED ULTRASOUND
Contrast-enhanced ultrasound (CEUS) shows promise as a
technique that will be beneicial in both endoscopic ultrasound
and transabdominal ultrasound of the pancreas. Historically,
CEUS was best considered an experimental technique. 98,196
However, more recent data suggest that CEUS may become much
more routine. 197-199 Fan states, “CEUS has obvious superiority
over conventional US in the general diagnostic accuracy of solid
pancreatic lesions and in the diagnostic consistency among
doctors. he performances of CEUS are similar to that of CECT
in the diagnosis of pancreatic carcinoma and focal pancreatitis.” 200
CEUS might be helpful in diagnosing pancreatic necrosis in
patients with severe acute pancreatitis. 147
Acknowledgment
he authors would like to acknowledge Dr. Philip Ralls, the prior
author of this chapter. His supreme dedication and passion for
quality ultrasound practice and education in all areas was
exemplary, and his images and text form the backbone of this
updated version.
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