Cystic lesions of the retroperitoneum can be classified as either neoplastic or nonneoplastic. Neoplastic lesions include cystic lymphangioma, mucinous cystadenoma, cystic teratoma, cystic mesothelioma, müllerian cyst, epidermoid cyst, tailgut cyst, bronchogenic cyst, cystic change in solid neoplasms, pseudomyxoma retroperitonei, and perianal mucinous carcinoma. Nonneoplastic lesions include pancreatic pseudocyst, nonpancreatic pseudocyst, lymphocele, urinoma, and hematoma. Because the clinical implications of and therapeutic strategies for retroperitoneal cystic masses vary depending on the cause, the ability to noninvasively differentiate between masses is important. Although there is substantial overlap of computed tomographic (CT) findings in various retroperitoneal cysts, some CT features, along with clinical characteristics, may suggest a specific diagnosis. CT may provide important information regarding lesion location, size, and shape; the presence and thickness of a wall; the presence of septa, calcifications, or fat; and involvement of adjacent structures. The most important clinical parameters include patient gender, age, symptoms, and clinical history. Familiarity with the CT and clinical features of various retroperitoneal cystic masses facilitates accurate diagnosis and treatment.

Actinomycosis, tuberculosis, and xanthogranulomatous inflammation are rare but specific causes of tubo-ovarian abscess (TOA). TOAs with these causes are frequently misdiagnosed as ovarian malignancies due to their unusual appearances at computed tomography (CT) and magnetic resonance (MR) imaging. Tubo-ovarian actinomycosis frequently has a predominantly solid appearance. A linear, solid, well-enhancing lesion extending directly from the mass is a characteristic CT and MR imaging finding. Small rim-enhancing lesions in the solid part of the mass are also suggestive of actinomycosis. Tuberculous TOAs usually mimic peritoneal carcinomatosis from ovarian cancers. The granulomatous and fibrotic nature of this infection may be reflected in the CT and MR imaging appearances, which can help in differentiation. TOAs from xanthogranulomatous inflammation demonstrate more nonspecific imaging findings than actinomycotic or tuberculous TOAs, although multiple xanthogranulomas in the mass may be seen on MR images. Knowledge of these characteristics can help one make the correct diagnosis and treat the patients appropriately.

The 64 MDCT is a promising technique for the detection and preoperative staging of gastric cancer.

Our results suggest that MRI may be useful in the diagnosis of tailgut cyst. A multilocular cystic mass in the presacral space is a characteristic MRI finding of tailgut cyst, which may also be revealed as a cystic mass consisting of a large cyst accompanied by a small peripheral cyst. However, further studies are necessary to establish the usefulness of MRI for evaluating tailgut cysts.

The androgens and androgen receptor (AR) play key roles in the prostate cancer (PCa) development and progression via epithelium-stroma cross talk. Prostate cancer-associated fibroblasts (CAFs) are dominant components in PCa stroma and are essential in the malignant progression by supporting tumorigenesis and metastasis. However, the AR roles in CAFs are still obscure. We isolated and immortalized the CAFs from human PCa tissues and found the CAFs are AR positive. We then knocked down their AR with siRNA and co-cultured the resultant CAFs with PCa cell line PC3. The MTT, invasion, and colony formation assays were performed to study the PC3 biological behavior. The results showed that the PCa epithelial growth, invasion, and colony formation abilities decreased when knocking down the CAFs AR. By using the real-time quantitative polymerase chain reaction, we found the IGF1, FGF7, FGF10, SDF1, HGF, and TGFb2 expression levels decreased in the AR knocked down CAFs. These results suggested that the AR in CAFs promoted PCa epithelial growth and invasion via regulating a series of growth factors. Targeting the AR in CAFs might be a potential therapeutic option for PCa in future.

ObjectiveThe purpose of our study was to describe acute necrotizing encephalopathy in Korean infants and children, and we sought to evaluate the prognostic factors.Materials and MethodsAcute necrotizing encephalopathy was diagnosed in 14 Korean infants and children. We retrospectively analyzed the neuroimaging findings including the follow-up changes. The clinical course of the disease was graded, and we evaluated prognostic factors including age, serum level of the aminotransferase, hemorrhage, and localized atrophy of the brain.ResultsThis encephalopathy predominantly affected the bilateral thalami (n=14), pons (n=12), and midbrain (n=10) in a symmetrical pattern. Hemorrhage was observed in eight patients (57%). On the follow-up images (n=12), the brain lesions were reduced in extent for all patients, and generalized atrophy was seen in six patients. Localized tissue loss was observed in five patients and a complete resolution occurred for one patient. All the patients survived and two recovered completely; mild (n=6) to severe (n=6) neurological deficits persisted in the remaining 12 patients. The significant prognostic factors identified in this study were the presence of hemorrhage (p = 0.009) and localized atrophy (p = 0.015).ConclusionAcute necrotizing encephalopathy in Korean patients showed the characteristic patterns of the post-infectious encephalopathy as described in the literature. The high survival rate and the relatively favorable clinical course observed for the present study suggest a more diverse spectrum of disease severity than was previously described. The presence of hemorrhage and localized tissue loss on MR images may suggest a poor prognosis.

Low-dose CT is highly effective for the diagnosis of suspected appendicitis and can be considered a valid alternative first-line imaging test that reduces the potential risk of exposure to ionizing radiation.

Although there was substantial overlap of sonographic findings in the various inguinal masses, clinical history and certain sonographic details can assist in making the correct diagnosis.