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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.

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.

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.

Purpose: To investigate a new image acquisition method [four dimensional T1-weighted high resolution imaging with volume excitation (4D THRIVE)] which enables an accurate hepatic arterial phase definition. The feasibility and its potential for detection and characterizing focal liver lesions (FLLs) are being evaluated. Materials and Methods: 115 FLLs underwent liver MRI that included the 4D THRIVE-contrast enhanced timing robust acquisition order (CENTRA)-keyhole sequence. Triple arterial phase was obtained during a single breath-hold. Images were reviewed for image quality, lesion conspicuity, and lesion detection. Two radiologists independently assessed images from phase I, II, III and through the triple arterial phase, which were all reviewed separately and in random order. The image quality was scored by using the five-point scale, and then, one phase for lesion with greatest conspicuity was selected. The enhancement pattern for FLLs was analyzed. Results: The detection rate was the highest on phase III. The image quality was greater than grade 3 with fair inter-observer agreements. The phase III showed greater conspicuity than phase I and II. Hepatocellular carcinomas (n = 38) showed variable enhancement pattern. Metastasis (n = 14) showed rim enhancement (n = 6), homogenous [n = 3) and no enhancement (n = 5). Most hemangiomas demonstrated homogenous enhancement (6/9, 67%). Conclusion: Triple arterial MRI using the 4D THRIVE-CENTRA-keyhole technique is feasible in despite of the relatively low detection rate, and is thus, helpful for the characterization of focal liver lesions. [ABSTRACT FROM AUTHOR]