case_images: PMC10972576_01
case_images: Preoperative computed tomography (CT) scan and endoscopic ultrasonography. a A 40-mm mass was found in the caudal part of the pancreas, with a 27-mm hypovascular mass (white arrow). b A hypoechoic tumor of approximately 30 mm was found in the tail of the pancreas (white arrow).
case_images: crg-2024-0018-0001-536008_F01.jpg
case_images: PMC10972576_01_crg-2024-0018-0001-536008_F01.jpg
case_images: F1
case_images: Contrast-enhanced computed tomography revealed a 40-mm mass in the tail of the pancreas, containing a 27-mm oligemic mass (Fig. 1a). Endoscopic ultrasonography also showed a hypoechoic tumor of approximately 30 mm in the pancreatic tail (Fig. 1b).
case_images: Macroscopic findings of resected specimen. a The tumor was resected with a part of the transverse colon (white arrow). However, there was no invasion of the PDAC by microscopic examination. b There was a 47 mm x 45 mm milky white mass with a clear border. Furthermore, another border was found in the tumor (white arrow).
case_images: crg-2024-0018-0001-536008_F02.jpg
case_images: PMC10972576_01_crg-2024-0018-0001-536008_F02.jpg
case_images: F2
case_images: The resected specimen comprised a milky white mass of 47 x 45 mm with clear borders (Fig. 2a, b).
case_images: Histopathological findings. a The border between inflammatory cell infiltration due to type 1 AIP and PDAC (hematoxylin-eosin stain, x40). b Fibrosis due to AIP was revealed (Elastica-Masson stain, x40). c There were many CD38-positive plasma cells infiltrating in the type 1 AIP area (CD38 immunohistochemical stain, x40). d The infiltrating plasma cells were also positive for IgG4 (IgG4 immunohistochemical staining, x40). e The IgG4/IgG-positive cell ratio was 45% (IgG immunohistochemical staining, x40).
case_images: crg-2024-0018-0001-536008_F03.jpg
case_images: PMC10972576_01_crg-2024-0018-0001-536008_F03.jpg
case_images: F3
case_images: This mass was covered with collagenous fibrous growths, and storiform fibrosis and phlebitis obliterans were also observed (Fig. 3a, b). In the area of fibrosis, immunostaining showed many CD38-positive cells and IgG4 expression, the exact number of IgG4-positive cells in magnified view was over 10, and IgG4/IgG-positive cell ratio was 45% (Fig. 3c-e).
case_images: Longitudinal course of this case.
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case_images: PMC10972576_01_crg-2024-0018-0001-536008_F04.jpg
case_images: F4
case_images: The longitudinal course of this case is shown in Figure 4.