Imaging pitfalls of pancreatic serous cystic neoplasm and its potential mimickers.

The aim of this article is to clarify diagnostic pitfalls of pancreatic serous cystic neoplasm (SCN) that may result in erroneous characterization. Usual and unusual imaging findings of SCN as well as potential SCN mimickers are presented. The diagnostic key of SCN is to look for a cluster of microcysts (honeycomb pattern), which may not be always found in the center. Fibrosis in SCN may be mistaken for a mural nodule of intraductal papillary mucinous neoplasm (IPMN). The absence of cyst wall enhancement may be helpful to distinguish SCN from mucinous cystic neoplasm. However, oligocystic SCN and branch duct type IPMN may morphologically overlap. In addition, solid serous adenoma, an extremely rare variant of SCN, is difficult to distinguish from neuroendocrine tumor.

FDG-PET Findings of Intraductal Oncocytic Papillary Neoplasms of the Pancreas: Two Case Reports.

Intraductal oncocytic papillary neoplasm (IOPN) of the pancreas is a rare pancreatic tumor. To date, there have been three case reports of IOPN which showed strong positivity on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), raising the possibility of distinguishing IOPNs from other intraductal papillary mucinous neoplasms (IPMNs) using FDG-PET. However, all three cases had large tumors, approximately 10 cm in diameter, and there are no case reports of FDG-PET findings of small IOPNs, i.e. tumors the average size of malignant IPMNs (3-5 cm). We report two cases with IOPN of average size with FDG-PET findings. Computed tomography (CT) showed a multilocular cystic lesion 4 cm in diameter with a mural nodule 1 cm in diameter (case 1) and a cystic lesion 5 cm in diameter with a papillary mural nodule 4 cm in diameter (case 2). FDG-PET showed abnormal uptake at the same location as the pancreatic tumor revealed by CT in both cases. The maximum standardized uptake values of the lesions were 3.4 and 4.2, respectively. Surgical resection was performed and the tumor was diagnosed as IOPN with carcinoma in situ (case 1) and IOPN with minimal invasion (case 2). FDG-PET may be useful for diagnosing malignancy in IOPN, as it is in IPMN. However, in our two cases, strong accumulation was not observed in the IOPNs, which were within the average size range of malignant IPMNs.

[Computed tomography colonography for 5 cases of pneumatosis cystoides intestinalis].

Computed tomography colonography (CTC) was performed in 5 patients with pneumatosis cystoides intestinalis (PCI). The virtual colonoscopy view of CTC as well as total colonoscopy (TCS) findings showed polypoid lesions in the colon, and multiplanar reconstruction images of the colon revealed in the polypoid lesions of the colon. We confirmed the diagnosis of PCI in all cases. CTC also detected the PCI lesions in the subserosa of the colonic wall which were not detected by TCS. Accurate evaluation of the extent of PCI involvement was obtained by CT air-contrast enema images. CTC is useful for detection of PCI lesions, assessment of the exact site and final diagnosis for PCI.

[A case of extrahepatic portal vein aneurysm with massive thrombosis].

A 59-year-old woman, who was given a diagnosis of portal vein aneurysm at another hospital 2 years previously, visited our institution complaining of abdominal pain in November 2005. Abdominal imaging including computed tomography and ultrasonography demonstrated that the portal vasculature had dilated to 5 cm in maximum dimension and its center was at the junction of the superior mesenteric vein and the splenic vein. Moreover, a large thrombus was seen in the portal vein, the superior mesenteric vein and the splenic vein. She was conservatively followed-up with warfarin. After 6 months, angiography revealed cavernous transformation around the portal vein was found with collateral flow toward the liver. At the time of writing the patient's condition is stable with neither extension of the thrombus nor constriction of the esophageal varices.

[Telangiectatic focal nodular hyperplasia accompanied with hemorrhage and necrosis during the course: report of a case].

A tumor, which was 10 cm in diameter, was found in the lateral segment of the liver of a 42-year-old man in October, 2004. The lesion was clinically diagnosed as focal nodular hyperplasia (FNH). In March, 2006, the patient admitted our hospital complaining epigastralgia, back pain, and fever. Hemorrhage and necrotic region was revealed within the tumor, hence lateral segmentectomy was carried out. The lesion was pathologically diagnosed as a telangiectatic FNH (T-FNH). A possibility that hemorrhage or necrosis may be induced within a T-FNH during its progress should be taken into consideration.