A rare case of peripancreatic Castleman's disease diagnosed preoperatively by endoscopic ultrasound-guided fine needle aspiration.

erative disorder of unknown etiology and has threepathologic variants: hyaline-vascular (HV), plasma cell (PC), and mixed type [1]. Two clinically relevant subtypes exist, the unicentric and multicentric variants. Unicentric pancreatic Castleman’s disease is very rare with only 13 reported cases [2–14]. We report on the endosonographic features of pancreatic Castleman’s disease and its preoperative diagnosis by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). A 27-year-old woman had a 4.2 × 4.3 cm, exophytic, hypervascular mass on arterial phase computed tomography (CT) (●" Fig. 1), which washed out on the venous phase images. EUS revealed a hypoechoic and hypervascular peripancreatic mass with a punctate calcification (●" Fig. 2). EUS-FNA was carried out and cytologic examination with flow cytometric analysis revealed polymorphous lymphocytes with a predominance of B lymphocytes, comprising a mixture of κand λ-bearing cells. Occasional morphologic features on cytologic smears (presence of variably sized and partially intact lymphoid follicles with traversing capillary vessels) and on cell block section (numerous lymphoid follicles with characteristic concentric rimming of lymphocytes) were compatible with a diagnosis of Castleman’s disease (●" Fig. 3). Laparotomy with excision of pancreatic mass was carried out without the need for pancreatic resection. Pathologic examination was consistent with an enlarged lymph node. The overall nodal architecture was preserved and there were numerous small follicles. Many of the follicles were atretic, and some contained two or more germinal centers. There was prominent concentric layering of peripheral lymphocytes around the follicles, creating an onion-skin pattern (●" Fig. 4). Hyaline deposits were present in many of the follicles. Interfollicular vascular proliferation was present, with some of the vessels penetrating the follicles, creating “lollipop” lesions. These characteristic pathologic features were consistent with A rare case of peripancreatic Castleman’s disease diagnosed preoperatively by endoscopic ultrasound-guided fine needle aspiration