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Pancreatic tumors are classified according to their histological type and grade in the WHO classification (Klöppel et al. 1996). Ductal adenocarcinoma comprises between 80% and 90% of all tumors of the exocrine pancreas.
Ductal adenocarcinoma usually presents as a solid mass with infiltrating growth margins. Ultrasonography typically shows a hypoechoic lesion, with roughly defined margins, often altering the gland contour. At pathology it is characteristic for the marked desmoplasia (Klöppel 1984), which justifies the hard tumoral consistency. At contrast-enhanced ultrasonography ductal adenocarcinoma enhancement is poor in all contrast-enhanced phases. The marked desmoplasia and the low mean vascular density of the lesion justify its features.
At CEUS ductal adenocarcinoma presents as a hypoechoic area compared to the adjacent pancreatic tissue with parenchymographic enhancement; margins and size of the lesion are better visible, and also the relationship with peripancreatic arterial and venous vessels for a local staging.
Endocrine tumors may induce specific clinical effects due to the hormonal production of the tumor (functioning endocrine tumors) or aspecific symptoms due to the expansive growth and the tumor size (non-functioning endocrine tumors). Endocrine tumors at Imaging appear hypervascular (Procacci et al. 2001d). Differential diagnosis through Imaging between NFETs and ductal adenocarcinoma is of fundamental importance for therapeutic strategy and prognosis (Procacci et al. 2001d). At color- and power-Doppler ultrasonography a “spots pattern” can be demonstrated inside the endocrine tumors (D’Onofrio et al. 2004). However a Doppler “silence” can be present in hypervascular endocrine tumors because of the small size of the lesion or of the vascular network of the tumor (D’Onofrio et al. 2004). At CEUS endocrine tumors show a rapid intense enhancement in the early contrast-enhanced phases (D’Onofrio et al. 2004).
Considering that the characterization of NFETs is mainly linked to the lesion’s frequent hypervascularization (Procacci et al. 2001d), a high sensitivity of imaging modalities in the detection of macrocirculation and microcirculation of the lesion is required.
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