Renal cell carcinoma (RCC) is a cause of significant morbidity and mortality, with an estimated 35,000 new cases and 12,480 deaths in the United States in 2003. Recent advances in imaging technology, pathology, urology, and oncology permit early diagnosis of RCC and facilitate optimal management. The 2004 World Health Organization classification for renal neoplasms recognizes several distinct histologic subtypes of RCC. These subtypes include clear cell RCC, papillary RCC, chromophobe RCC, hereditary cancer syndromes, multilocular cystic RCC, collecting duct carcinoma, medullary carcinoma, mucinous tubular and spindle cell carcinoma, neuroblastoma-associated RCC, Xp11.2 translocation-TFE3 carcinoma, and unclassified lesions. Different histologic subtypes of RCC have characteristic histomorphologic and biologic profiles. Clear cell RCC is the most common subtype and has a less favorable prognosis (stage for stage) than do papillary RCC and chromophobe RCC. Collecting duct carcinoma and renal medullary carcinoma are associated with aggressive clinical behavior and a poor prognosis.
Fat-containing tumors of the liver are a heterogeneous group of tumors with characteristic histologic features, variable biologic profiles, and variable imaging findings. Benign liver lesions that contain fat include focal or geographic fatty change (steatosis), pseudolesions due to postoperative packing material (omentum), adenoma, focal nodular hyperplasia, lipoma, angiomyolipoma, cystic teratoma, hepatic adrenal rest tumor, pseudolipoma of the Glisson capsule, and xanthomatous lesions in Langerhans cell histiocytosis. Malignant liver lesions that can contain fat include hepatocellular carcinoma, primary and metastatic liposarcoma, and hepatic metastases. Identification of fat within a liver lesion can be critical in characterization of the lesion. The imaging characteristics of a lesion coupled with the pattern of intratumoral fatty change are helpful in narrowing the differential diagnosis. Although the presence of fat can be demonstrated with computed tomography or ultrasound, magnetic resonance imaging is the most specific imaging technique for demonstration of both microscopic and macroscopic fat.
Renal cell carcinoma (RCC) is the most common malignant tumor involving the kidney. Determining the subtypes of renal cell carcinoma is among the major goals of preoperative radiological work-up. Among all modalities, magnetic resonance imaging (MRI) has several advantages, such as inherent soft tissue contrast, detection of lipid and blood products, and excellent sensitivity to detect small amounts of intravenous contrast, which facilitate the discrimination of subtypes of RCC. In this article, we review MRI and pathological features used for determining the main histologic subtypes of RCC, including clear cell, papillary, collecting duct, chromophobe, multilocular cystic, and unclassified RCC. Renal cell carcinoma (RCC) is the most common malignant epithelial tumor of the kidney, accounting for 85%-90% of all solid renal tumors in adults and comprising 1%-3% of all malignant visceral neoplasms (1). Approximately 40% of patients with RCC eventually die from progression of this disease, making it the most lethal urologic malignancy (2). Today, most RCC instances are incidental masses identified on imaging studies performed for nonurological reasons.Percutaneous biopsy is a minimally invasive method, and its accuracy for identifying renal tumors ranges from 70% to 90% (3, 4). However, widespread use of percutaneous biopsy remains controversial due to the potential complications of biopsy, the possibility of sampling errors, the dependence on an adequate biopsy sample for analysis, and concerns about how the biopsy information might alter the treatment plan (5). Therefore, histopathological characterization of renal masses with magnetic resonance imaging (MRI) compared with percutaneous biopsy becomes more advantageous.Determining subtypes of RCC has significant prognostic and theraupeutic implications for patients who are poor surgical candidates, for patients who have a metastatic disease, for surgical planning in patients who are surgical candidates, and for immunotherapy and use of the tyrosine kinase inhibitors "sunitinib" and "sorafenib" for clear cell RCC and "temsirolimus" for papillary RCC (6-9).The need for a different approach to the management of RCC among classical surgical procedures has arisen. Nephron-preserving surgical methods, cryoablation, radiofrequency ablation, targeted molecular therapy or follow-up, and MRI are believed to surpass other modalities both in the diagnosis of RCC and determination of its subtypes (10,11).In this article, we review MRI findings and pathological features used for determining the main histologic subtypes of RCC, including clear cell carcinoma, papillary, collecting duct, chromophobe, multilocular cystic, and unclassified RCC. The role of MRI in renal imagingThere are three indispensable components of renal MRI: breathhold imaging, three-dimensional (3D) gradient echo pulse sequence, and fat detection techniques.Breathhold imaging is one of the essential techniques in renal mass MRI protocols. Suspended expiration eliminates respiratory motion artifacts an...
This article is a review of magnetic resonance imaging (MRI) of incidental focal liver lesions. This review provides an overview of liver MRI protocol, diffusion-weighted imaging, and contrast agents. Additionally, the most commonly encountered benign and malignant lesions are discussed with emphasis on imaging appearance and the diagnostic performance of MRI based on a review of the literature. (HEPATOLOGY 2011;54:2227-2237 T he incidence of incidentally detected focal liver lesions (FLL) parallels growth in imaging utilization. The majority of FLL arising in noncirrhotic livers are benign. Hemangiomas, focal nodular hyperplasias (FNH), and adenomas (HCA) are the most commonly encountered solid benign lesions. 1-3The most commonly encountered malignant lesions in noncirrhotic livers are metastases. Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) occur in the setting of chronic liver disease.Maximizing specificity and accuracy of cross-sectional imaging in the context of these incidental liver lesions is paramount in avoiding unnecessary biopsies, which may portend a postprocedural morbidity of 2.0% to 4.8% and mortality of 0.05%. [4][5][6] Ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) are the main liver imaging modalities. A meta-analysis comparing contrast-enhanced ultrasound, CT, and MRI in evaluating incidental FLLs demonstrated similar diagnostic performance with specificities ranging from 82%-89% and no significant difference in the summary receiver operating characteristic between modalities.7 Given the lack of ionizing radiation and relative nonavailability of ultrasound contrast in the U.S., MRI is the imaging test of choice for FLL characterization, demonstrating similar if not superior performance to CT. This review focuses on the diagnostic performance of MRI in evaluating the most common FLL in noncirrhotic livers with additional discussion of HCC and ICC, which, although highly associated with chronic liver disease, are important differential considerations. Liver MRIBasic Protocol. A comprehensive liver protocol evaluates the parenchyma, vasculature, and biliary system. This is accomplished by way of a combination of single-shot T2-weighted fast spin-echo, gradient echo T1-weighted in-and opposed-phase, fat suppressed T2-weighted, dynamic pre-and postcontrast T1-weighted imaging and potentially subtraction of prefrom postcontrast image sets.8 High-quality images require compromise between achievable resolution and the need for breath-holding, which limits each sequence to 20 seconds or less. Breath-holding is not always possible in sick patients. As a result, modifications to the basic protocol may include the addition of free-breathing sequences, respiratory-gating, motion correction techniques (i.e., BLADE or PROPELLER or radial acquisition of k-space).MRI quality can be variable due to differences in sequences, gradient, and magnetic field strength. In recognition of this variability, a recent publication on behalf
Background & Objectives Multidisciplinary tumor boards (MDTBs) are frequently employed in cancer centers but their value has been debated. We reviewed the decision-making process and resource utilization of our MDTB to assess its utility in the management of pancreatic and upper gastrointestinal tract conditions. Methods A prospectively-collected database was reviewed over a 12-month period. The primary outcome was change in management plan as a result of case discussion. Secondary outcomes included resources required to hold MDTB, survival, and adherence to treatment guidelines. Results 470 cases were reviewed. MDTB resulted in a change in the proposed plan of management in 101 of 402 evaluable cases (25.1%). New plans favored obtaining additional diagnostic workup. No recorded variables were associated with a change in plan. For newly-diagnosed cases of pancreatic ductal adenocarcinoma (n=33), survival time was not impacted by MDTB (p=.154) and adherence to National Comprehensive Cancer Network guidelines was 100%. The estimated cost of physician time per case reviewed was $190. Conclusions Our MDTB influences treatment decisions in a sizeable number of cases with excellent adherence to national guidelines. However, this requires significant time expenditure and may not impact outcomes. Regular assessments of the effectiveness of MDTBs should be undertaken.
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