Metastatic Renal Cell Carcinoma Manifesting as a Gastric Polyp on CT: A Case Report and Literature Review

Gastric metastasis from renal cell carcinoma (RCC) is extremely rare, occurring in 0.2% of all RCC cases. Owing to its low prevalence, metachronous gastric metastasis from RCC may be underdiagnosed, and the imaging findings have not been well-established. Herein we present a case of metastatic RCC manifesting as a gastric polyp in a 70-year-old female along with a literature review on the imaging findings of gastric metastases from RCC. In patients presenting with gastric hyper-enhancing polypoid masses, metastasis from RCC should be considered as a differential diagnosis.

Radiomics Analysis of Magnetic Resonance Proton Density Fat Fraction for the Diagnosis of Hepatic Steatosis in Patients With Suspected NonAlcoholic Fatty Liver Disease

Background@#This study aimed to assess the diagnostic feasibility of radiomics analysis based on magnetic resonance (MR)-proton density fat fraction (PDFF) for grading hepatic steatosis in patients with suspected non-alcoholic fatty liver disease (NAFLD). @*Methods@#This retrospective study included 106 patients with suspected NAFLD who underwent a hepatic parenchymal biopsy. MR-PDFF and MR spectroscopy were performed on all patients using a 3.0-T scanner. Following whole-volume segmentation of the MRPDFF images, 833 radiomic features were analyzed using a commercial program. Radiologic features were analyzed, including median and mean values of the multiple regions of interest and variable clinical features. A random forest regressor was used to extract the important radiomic, radiologic, and clinical features. The model was trained using 20 repeated 10-fold cross-validations to classify the NAFLD steatosis grade. The area under the receiver operating characteristic curve (AUROC) was evaluated using a classifier to diagnose steatosis grades. @*Results@#The levels of pathological hepatic steatosis were classified as low-grade steatosis (grade, 0–1; n = 82) and high-grade steatosis (grade, 2–3; n = 24). Fifteen important features were extracted from the radiomic analysis, with the three most important being wavelet-LLL neighboring gray tone difference matrix coarseness, original first-order mean, and 90th percentile. The MR spectroscopy mean value was extracted as a more important feature than the MR-PDFF mean or median in radiologic measures. Alanine aminotransferase has been identified as the most important clinical feature. The AUROC of the classifier using radiomics was comparable to that of radiologic measures (0.94 ± 0.09 and 0.96 ± 0.08, respectively). @*Conclusion@#MR-PDFF-derived radiomics may provide a comparable alternative for grading hepatic steatosis in patients with suspected NAFLD.

A Rare Case of Small Bowel Undifferentiated Pleomorphic Sarcoma: Imaging Findings on CT and Magnetic Resonance Enterography

Gastrointestinal tract involvement in undifferentiated pleomorphic sarcoma (UPS) is extremely rare. To the authors' knowledge, only 21 cases of primary small bowel UPS have been reported in the literature available in English. Reported CT findings in primary small bowel UPS have been nonspecific, and MRI findings have been reported in only one case. The present article describes a case involving a 72-year-old male with histologically confirmed primary UPS arising from the ileum, focusing on both CT and magnetic resonance enterography findings. On CT, primary small bowel UPS was noted as a heterogeneously enhanced small bowel mass without obstruction. Magnetic resonance enterography revealed heterogeneous intermediate T1 and T2 signal intensity, with hemorrhagic or necrotic foci within the mass and heterogeneous enhancement. The differential diagnosis included malignant gastrointestinal tumor; however, the prognosis of UPS is worse, with higher incidences of extra-abdominal metastasis.

Radiologic Findings of Renal Schwannoma: A Case Report and Literature Review

Schwannoma is a benign nerve sheath tumor that involves Schwann cells mostly found in the head, neck, posterior mediastinum and extremities. Schwannoma develops rarely in the retroperitoneum; thus, renal schwannoma is extremely uncommon. Differentiation of renal schwannoma from renal cell carcinoma is difficult with radiologic analysis. A few cases of these tumors have been reported in literature, and little has been described regarding imaging appearances. In this study, we present a rare case of a renal schwannoma, resembling renal cell carcinoma, with radiological correlations.

Ultrasonography of acute flank pain: a focus on renal stones and acute pyelonephritis

Ultrasonography is a useful tool for the differential diagnosis of acute flank pain. Renal stones appear as a focal area of echogenicity with acoustic shadowing on ultrasonography. In acute pyelonephritis (APN), the kidneys may be enlarged and have a hypoechoic parenchyma with loss of the normal corticomedullary junction. However, clinical and laboratory correlations are essential for the diagnosis of renal stones and APN through imaging studies. This review describes the typical ultrasonography features of renal stones and APN. Moreover, in daily practice, cross-sectional imaging is essential and widely used to confirm renal stones and APN and to differentiate them from other diseases causing flank pain. Other diseases causing acute flank pain are also described in this review.

Progressive Transformation of Germinal Centers in Presacral Space: MRI Findings and Literature Review

Progressive transformation of germinal centers (PTGC) is an atypical feature seen in lymph nodes with unknown pathogenesis. PTGC most commonly presents in adolescent and young adult males as solitary painless lymphadenopathy with various durations. Cervical nodes are the most commonly involved ones while involvements of axillary and inguinal nodes are less frequent. PTGC develops extremely rarely in other locations. We report a rare case of solitary mass present in the presacral space. The mass as subsequently proven to be PTGC. To the best of our knowledge, PTGC in the presacral space has not been previously reported in the literature.

MRI Findings of Obstructed Hemivagina and Ipsilateral Renal Agenesis (OHVIRA syndrome) with a Blind Megaureter: Case Report

Obstructed hemivagina and ipsilateral renal anomaly (OHVIRA) syndrome is an uncommon congenital abnormality of the female urogenital tract characterized by the triad of uterine didelphys, obstructed hemivagina, and ipsilateral renal agenesis. A 13-year-old female presented with acute lower abdominal pain. Magnetic resonance imaging (MRI) revealed uterine didelphys, hematometrocolpos, obstructed hemivagina, and right ipsilateral agenesis, consistent with OHVIRA syndrome. Also, a well-defined mass with fluid signal intensity, mimicking adnexal neoplasm was seen in the right lower pelvic cavity adjacent to the posterior wall of the bladder. Vaginal septotomy and drainage of hematometrocolpos were done initially, but unilateral hysterectomy was later performed to relieve the patient's symptoms. The cystic mass in the right lower pelvic cavity was also excised and confirmed as a blind megaureter.

MR Imaging Findings of Tamoxifen-associated Uterine Adenosarcoma: Report of Two Cases

Adenosarcoma of the uterus is a rare biphasic tumor containing benign glandular epithelial and malignant mesenchymal components. The tumor has been reported to be associated with antiestrogen therapy, particularly tamoxifen, but there have been a few case reports with MRI. We present two cases of MRI findings of uterine adenosarcoma after antiestrogen therapy, tamoxifen and toremifene in breast cancer patients. The tumor presents as a large polypoid mass occupying the endometrial cavity, and may protrude into the vagina. On MRI, the tumor typically shows solid components with scattered small cysts and heterogeneous enhancement. These findings are not significantly different from conventional adenosarcoma.

Unusual venous route of pulmonary artery catheter in a liver transplant recipient: pericardiophrenic or highest intercostal vein?: a case report / 대한마취과학회지

We report an extraordinary case in which the venous route for pulmonary artery catheterization was unusual. A 41 year-old woman with an end-stage liver disease underwent a living-donor liver transplantation. After induction of anesthesia, the pulmonary artery catheter was revealed to be advanced into the left brachiocephalic vein and then slipped into another vein that drains into the left brachiocephalic vein. In this case, we assumed that the catheter had most likely slipped into the left pericardiophrenic vein since the catheter follows the left heart border similarly to the route of this vein according to the chest X-ray. Patients with liver cirrhosis develop many collateral vessels and have enlarged veins due to portal hypertension, which makes this vascular route possible. We present this case for anesthesiologists to be aware of the possibilities of unusual venous route due to dilated collateral vessels especially in liver transplant patients.