PMC6000737_01
Preoperative imaging detected a multilocular cystic mass in the retroperitoneum.. (A, B) Contrast-enhanced CT shows the cystic mass located in the retroperitoneum, caudal to the pancreatic body (arrows). The lateral part of the multilocular cyst had a higher CT value and internal bleeding was suspected. (C) Contrast-enhanced MRI; T1-weighted image (T1WI) and (D) T2-weighted image (T2WI). The medial part of the cystic mass shows low intensity in T1WI and high intensity in T2WI, suggesting a watery substance. On the other hand, the lateral part of the cystic mass shows higher intensity both in T1WI and T2WI, and old bleeding was suspected.
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Contrast-enhanced computed tomography (CT) showed a 5-cm multilocular cystic mass located in the retroperitoneum, caudal to the pancreatic body (Fig. 1A, B). CA19-9, and DUPAN-2. Contrast-enhanced magnetic resonance imaging (MRI) also showed a multilocular cystic mass with old internal bleeding (Fig. 1C, D).
Preoperative 3D imaging and intraoperative finding.. (A, B) A 3D reconstruction image from CT angiography; (A) The drainage vein from the upper part of the cystic mass flows into the splenic vein (arrow). (B) Dorsal view shows a feeder artery from the left renal artery runs into the back side of the cystic mass (arrow). (C, D) Laparoscopic image; (C) The spherical cystic mass was identified as caudal to the pancreatic body. (D) The feeding artery branches from the left renal artery (arrow).
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CT taken for blood vessel evaluation 2 months after the first admission showed no significant change in the size of the cystic mass. CT angiography showed that the cystic mass had blood supply from the left renal artery (Fig. 2B) and the drainage vein flowed into the splenic vein (Fig. 2A). The cystic mass was clearly separated off from the pancreas, and the drainage vein flow into the splenic vein was clipped and cut (Fig. 2C). By dissecting the serosa of the transverse mesocolon, the cystic mass was mobilized from the retroperitoneal connective tissue, and the feeding artery from the left renal artery was clipped and cut to excise the cystic mass (Fig. 2D).
Macro- and microscopic images of the resected specimen.. (A, B) A macro image of the cystic mass; it was 52 x 40 x 30 mm multilocular cyst filled with mucinous fluid. A chamber of the multilocular cyst was filled with a blood clot. (C, D) A microscopic image; (C) Most of the cystic wall had a flat columnar epithelium. (D) Some parts of the cyst showed a villous-like structure and two smooth muscular layers. There was no evidence of malignancy.
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The specimen was a multilocular cyst with mucosal fluid, and one of the chambers was filled with clotted blood (Fig. 3A, B). A part of the lining was a flat simple columnar epithelium (Fig. 3C), and other parts showed a villous-like structure (Fig. 3D).