PMC5340951_01
CAT scan ((a) and (b)) and magnetic resonance ((c) and (d)) images before the surgery. (a) Pancreatic head increased in size, with focal calcification, without mass lesion. (b) Dilated pancreatic duct in the whole pancreas, with major diameter, and fusiform dilatation in the pancreatic head. Slight atrophy of pancreatic parenchyma. (c) Fusiform dilated main pancreatic duct in the pancreatic head, with small filling defect suspected. (d) Dilated main pancreatic duct in pancreatic body and tail, with slight atrophy of parenchyma.
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A CAT scan was performed, finding multiple calcifications and irregularly dilated main pancreatic duct, predominantly in the pancreatic head (Figures 1(a) and 1(b)), where the dilatation had some cystic aspect and was disproportionally more pronounced than in the pancreatic body and tail. The same alterations were confirmed by MRI (Figures 1(c) and 1(d)), without intramural nodules in the dilated main duct.
ERCP. (a) ERCP: incomplete contrast injection in the pancreatic duct. Cystic dilatation of the main pancreatic duct in the head of pancreas; initial opacification of less dilated duct in the body. Note normal caliber duct in uncinated process. (b) Pancreatic papillotomy, followed by passage of white pancreatic stone. No mucin was seen at this moment. (c) "Fish eye" sign; mucin spurring from the minor papilla. (d) Flow of mucin from the minor papilla.
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ERCP was performed, and contrast injection revealed a cystic dilation of main pancreatic duct in the head (Figure 2(a)). Through pancreatic papillotomy, typical whitish pancreatic stone passed into the duodenal lumen (Figure 2(b)). However, after having continued the contrast injection, mucin passage was seen producing the typical fish eye appearance in the major and also the minor papilla (Figures 2(c) and 2(d)).
Histologic findings. Hematoxylin-eosin, 100x. (a) Neoplastic epithelium of a pancreatic duct, with formation of papillary structures (on the right). Abundant mucin formation on the left side. (b) Mucinous uniform cells with epithelial atypia and invasion of the neighborhood. (c) Tumor-free pancreatic tissue. Distortion of the normal architecture; moderate-to-severe fibrosis is seen with inflammatory cell infiltration. We can observe dilated ductal elements and atrophy of acinar cells.
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Histological (Figure 3) findings confirmed the existence of a mucinous tumor emerging from the main pancreatic duct, with multiple foci of high grade dysplasia and even with evident transformation into an infiltrative malignant lesion (Figure 3).