US and CT Findings of Small Renal Cell Carcinoma

PURPOSE: To evaluate US and CT characteristics of small renal cell carcinomas with diameter less than 3cm. MATERIALS AND METHODS: We retrospectively analysed US and CT findings of the small renal cell carcinomas which were surgically confirmed. We analysed echogenicity, peritumoral hypoechoic rim, intratumoral cysts on US. We analysed CT with viewpoints of tumor margin, growth pattern, renal contour change, attenuation on pre- and postcontrast scan, homogeneity, and perirenal changes. RESULTS: The US characteristics of the small renal cell carcinomas were hyperechogenicity(89%), peritumoral hypoechoic rim(66%) and intratumoral cysts(44%). They had relatively well-defined margin(90%), smooth and round contour(90%), endophytic growth pattern(65%), and outward bulging of renal contour(75%) on CT. They had iso- or high attenuation(87%) on precontrast CT, and were relatively homogeneous low-attenuated on postcontrast CT. CONCLUSION: The constellation of US and CT findings may be helpful in the diagnosis and understanding of the internal architecture of the small renal cell carcinomas.

Cushing's Disease: The Diagnostic Value of Radiologic Studies

PURPOSE: To evaluate the diagnostic value of radiologic studies in the Cushing's disease MATERIALS AND METHODS: We analyzed retrospectively the CT(n=19, dynamic CT was not perfomed), MR (n=23, dynamic MR in 2 cases), and the results of inferior petrosal sinus sampling(IPSS)(n=13) in 25 patients(19 women, 6men, age range 16-58, mean 32.2) with pathologically-confirmed ACTH secreting pituitary adenoma. We analyzed the radiologic findings and determined how accurately each method could detect and lateralize the lesion within the pituitary gland. The results were compared with the surgical findings and with each other. RESULTS: Seven patients(28%) out of 25 had macroadenomas and the lesions were detected and correctly diagnosed by CT and MR in all. Eighteen patients(72%) had microadenoma. In patients with microadenoma the sensitivity was 38.5%(5/13) in CT, 64.7%(11/17) in MR, 90.9%(10/11) in IPSS. In two patients with dynamic MR, in whom the conventional Gd-enhanced MR showed false negative results, the lesions were detected as low signal intensity mass and correctly lateralized. Considering the results of both MR and IPSS, the sensitivity increased up to 94.1%(17/18). CONCLUSION: Considering the invasiveness of IPSS, Gd-enhanced MR, preferably dynamic, seems to be an imaging modality of choice in Cushing's disease. Combined use of IPSS in selected patients further increases the accuracy of diagnosis and lateralization.

MR Findings of Extraabdominal Desmold Tumors: Correlation with H istopathologic Findings

PURPOSE: To understand the MR findings of extraabdominal desmold tumors by correlation with histopathologic findings. MATERIALS AND METHODS: MR images of histologically proved 12 patients with extraabdominal desmold tumor were retrospectively reviewed. Three types of MR features were defined; type I had signal changes on T1 and T2 weighted images and relatively homogeneous nature, type II had homogeneously low signal intensities on T1 and T2 weighted images and type III was a mixed form of type I and type II. Signal intensity, enhancement pattern and margin of the lesions were analyzed on MR images. Pathologic features were analyzed by three aspects, which were cellularity, amount of collagen and vascularity, and were correlated with MR images. RESULTS: The signal intensities of type I desmolds were intermediate on T1 weighted image and higher on T2 weighted image with localized margin and gadolinium enhancement. Pathologically this type showed predominant cellularity and vascularity. The signal intensities of type II desmold were homogenous low signal intensities on both T1 and T2 weighted images without enhancement. Pathologically this type showed predominant collagen components and hypovascularity. Type III desmolds were mixed form of type I and type II on MR images as well as on pathologic features. Type I and type II desmold tumors had localized margins, however type III had both localized and infiltrative margins. CONCLUSION: The MR findings of extraabdominal desmold tumors would reflect the pathologic background of the tumor.