Pancreatic neuroendocrine neoplasms: Magnetic resonance imaging features according to grade and stage

Figure 1 Small hyperfunctioning pancreatic neuroendocrine neoplasm (insulinoma) classified as G1, stage 1 tumor at histology (Ki67 < 1%, T1, N0, M0) in a 44 years-old woman. A: Axial volumetric interpolated breath-hold examination (VIBE) gradient echo image (repetition time msec/echo time msec, 4.3/1.4) with fat suppression shows a homogeneously hypointense lesion with well defined margins (arrow) in the pancreatic body; B: On axial T2-weighted half-Fourier single-shot turbo spin echo (HASTE) image (TR/TE, ∞/90), the tumor appears slightly hyperintense (arrow) compared to adjacent pancreatic parenchyma; C: At ADC quantification the tumor had a relatively high mean ADC value; D: The macroscopic pathological specimen (distal pancreatectomy, sagittal cut) shows a small, well-delimitated lesion bulging the contour of the pancreatic body.

Figure 2 Non-hyperfunctioning pancreatic neuroendocrine neoplasm of the pancreatic head classified as G2, stage 3b tumor at histology (Ki67 15%, T4, N1, M0) in a 55 years-old man. A: Axial volumetric interpolated breath-hold examination (VIBE) gradient echo image (repetition time msec/echo time msec, 4.3/1.4) with fat suppression shows a hypointense tumor with ill-defined margins (arrow); B: On coronal fat-saturated T1-weighted volumetric interpolated breath-hold examination (VIBE) gradient echo image (TR/TE 3.5/1.3 ms) acquired during the delayed phase of the dynamic study the tumor shows heterogeneous contrast enhancement, with infiltration of the superior mesenteric vein (arrow); C: The tumor presents intermediate mean ADC value; D: The surgical specimen (pancreaticoduodenectomy with en bloc resection of the superior mesenteric vein, transverse cut) shows a large lesion of the pancreatic head with irregular margins infiltrating the superior mesenteric vein (arrow).

Figure 3 Non-hyperfunctioning pancreatic neuroendocrine neoplasm of the pancreatic head classified as G3, stage 3b tumor at histology (Ki67 60%, T4, N1, M0) in a 76 years-old woman. A: Axial T2-weighted half-Fourier single-shot turbo spin echo (HASTE) image (TR/TE, ∞/90) shows a large, slightly hyperintense tumor in the pancreatic head (arrow); B: On coronal fat-saturated T1-weighted volumetric interpolated breath-hold examination (VIBE) gradient echo image (TR/TE 3.5/1.3 ms) acquired during the delayed phase of the dynamic study the tumor shows heterogeneous contrast enhancement (arrow); C: At quantitative analysis of ADC map the tumor shows low mean ADC value; D: The surgical specimen (pancreaticoduodenectomy, sagittal cut) shows a large lesion of the pancreatic head with heterogeneous aspect.