Peritoneal dissemination of pancreatic cancer caused by endoscopic ultrasound-guided fine needle aspiration: A case report and literature review

Figure 2 Pathological findings. A: Specimens obtained via endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) biopsy. Atypical cells with enlarged and hyperchromatic nuclei infiltrating the fibrous stroma are visible; B: A fresh gross image of the resected pancreas: a poorly circumscribed whitish tumor mass (arrowheads) is observed within pancreas parenchyma at the cut surface. Two areas of peritoneal thickening with reddish (asterisk) and whitish (dagger) appearance are observed at a distance from the tumor site; C: The cut surface of the formalin-fixed specimen: the peritoneal side is on the right, and the retroperitoneal side on the left; D: Histological image of the main tumor: the tumor is predominantly composed of poorly differentiated carcinoma cells with ill-defined ductular structures; E: A loupe image correspondence to the macroscopic image observed in panel C: the area surrounded by black dots is the main tumor lesion. A trabecular fibrotic scar (arrows) associated with peritoneal surface hemorrhage (asterisks) is observed; F: A low-power view of the fibrotic scar (arrows in E) possibly due to the needle tract injected during EUS-FNA; G: A high-magnification image of hemorrhagic peritoneum (asterisks in B, C, and E) proximal to the fibrotic scar. In this area (considered to be the needle puncture site), small aggregates of tumor cells (inset) are embedded in the fibrotic stroma; H: A high-power microscopic view of the whitish thickened peritoneum (dagger in B). Disseminated tumor cells focally forming the ductular structures are seen on the surface of the serosa.