Liver Masses: What Physicians Need to Know About Ordering and Interpreting Liver Imaging.

PURPOSE OF REVIEW: This paper reviews diagnostic imaging techniques used to characterize liver masses and the imaging characteristics of the most common liver masses. RECENT FINDINGS: The role of recently adopted ultrasound and magnetic resonance imaging contrast agents will be emphasized. Contrast-enhanced ultrasound is an inexpensive exam which can confirm benignity of certain liver masses without ionizing radiation. Magnetic resonance imaging using hepatocyte-specific gadolinium-based contrast agents can help confirm or narrow the differential diagnosis of liver masses.

Case 233: Blastomycosis.

History A 35-year-old man from the upper Midwest region of the United States who had no relevant medical history initially presented to an acute care clinic with multiple small tender skin lesions. His temperature was 38.1°C, and physical examination revealed several small fluctuant masses that were draining purulent material. Skin culture of one of the draining lesions was performed at this time, but there was no subsequent bacterial growth. A diagnosis of furunculosis was made, and Bactrim (sulfamethoxazole-trimethoprim; AR Scientific, Philadelphia, Pa) and a regimen of chlorhexidine washes were prescribed. Two weeks later, the number of skin lesions had increased, and the patient had begun to experience night sweats and fevers. After an episode of hemoptysis and some unusual pain in the patient's right testicle, he presented to the emergency department. At this time, chest radiographs were obtained. The patient was admitted for additional work-up, and computed tomographic (CT) images of the chest were obtained. Physical examination at the time of admission revealed scattered 1-3-cm firm pink hyperpigmented subcutaneous nodules, several of which had overlying pustules. This examination was also notable for a palpable fullness within the right testicle. The patient was afebrile at admission. He denied a history of contact with sick people, illicit drug use, or recent travel. His social history was notable for a 20-pack-year smoking history and a recent relocation to a neighborhood with several new construction sites. Laboratory evaluation revealed leukocytosis (white blood cell count, 15.4 × 10(9)/L; normal range, [3.5-10.5] × 10(9)/L), a chemistry panel revealed a low sodium level (132 mEq/L [132 mmol/L]; normal range, 134-142 mEq/L [134-142 mmol/L]), and serum α-fetoprotein and human chorionic gonadotropin levels were normal. Ultrasonography (US) of the scrotum was performed. Serum analysis was negative for human immunodeficiency virus type 1 and type 2 RNA, and Venereal Disease Research Laboratory and rapid plasma regain test results were negative. Blood cultures were negative for bacterial growth. On the basis of chest CT findings, bronchoscopy with bronchoalveolar lavage was performed. Magnetic resonance (MR) imaging of the abdomen also was performed to further evaluate a focal area of hypoenhancement within the pancreatic tail seen on chest CT images.

Imaging of adrenal and renal hemorrhage.

Hemorrhage of the kidneys and adrenal glands has many etiologies. In the adrenal glands, trauma, anticoagulation, stress, sepsis, surgery, and neoplasms are common causes of hemorrhage. In the kidneys, reasons for hemorrhage include trauma, bleeding diathesis, vascular diseases, infection, infarction, hemorrhagic cyst rupture, the Antopol-Goldman lesion, and neoplasms. Angiomyolipoma and renal cell carcinoma are the neoplasms most commonly associated with hemorrhage in the kidneys and adrenal cortical carcinoma, metastases, and pheochromocytoma are associated with hemorrhage in the adrenal glands. Understanding the computed tomography and magnetic resonance imaging features, and causes of hemorrhage in the kidneys and adrenal glands is critical. It is also important to keep in mind that mimickers of hemorrhage exist, including lymphoma in both the kidneys and adrenal glands, and melanoma metastases in the adrenal glands. Appropriate imaging follow-up of renal and adrenal hemorrhage should occur to exclude an underlying malignancy as the cause. If there is suspicion for malignancy that cannot be definitively diagnosed on imaging, surgery or biopsy may be warranted. Angiography may be indicated when there is a suspected underlying vascular disease. Unnecessary intervention, such as nephrectomy, may be avoided in patients with benign causes or no underlying disease. Appropriate management is dependent on accurate diagnosis of the cause of renal or adrenal hemorrhage and it is incumbent upon the radiologist to determine the etiology.

Imaging features of benign and malignant ampullary and periampullary lesions.

The ampulla of Vater is an important anatomic landmark where the common bile duct and main pancreatic duct converge in the major duodenal papilla. Imaging evaluation of the ampulla and periampullary region poses a unique diagnostic challenge to radiologists because of the region's complex and variable anatomy and the variety of lesions that can occur. Lesions intrinsic to the ampulla and involved segment of the biliary tree can be neoplastic, inflammatory, or congenital. Neoplastic lesions include ampullary adenocarcinomas and adenomas, which often are difficult to differentiate, as well as pancreatic or duodenal adenocarcinomas, pancreatic neuroendocrine tumors, and cholangiocarcinomas. Ultrasonography (US), computed tomography, magnetic resonance (MR) imaging, and MR cholangiopancreatography are commonly used to evaluate this region. Endoscopic retrograde cholangiopancreatography or endoscopic US examination may be necessary for more definitive evaluation. Periampullary conditions in the duodenum that may secondarily involve the ampulla include neoplasms, duodenitis, duodenal diverticula, and Brunner's gland hyperplasia or hamartomas. Because these lesions can exhibit a wide overlap of imaging features and subtle or nonspecific imaging findings, diagnosis is made on the basis of patient age, clinical history, and imaging and laboratory findings. Given the complexity of imaging evaluation of the ampulla and periampullary region, it is essential for radiologists to understand the variety of lesions that can occur and recognize their imaging characteristics.

Imaging of Benign Hepatic lesions.

As abdominal imaging volumes have increased, the incidence of incidentally identified benign hepatic lesions has substantially increased. Familiarity with imaging appearances of benign hepatic tumors, both common and less commonly encountered, allows the radiologist to give an informed differential diagnosis. In addition to clinical history, awareness of imaging findings of benign hepatic lesions on ultrasound, computed tomography and magnetic resonance imaging is useful in evaluating these lesions and avoiding unnecessary diagnostic interventions or imaging surveillance.

Imaging of Intrahepatic Cholangiocarcinoma.

Cholangiocarcinoma is the second most common primary hepatic malignancy and is a heterogeneous tumor of biliary epithelium. We discuss the risk factors, anatomic classification of cholangiocarcinoma (CC) as well as the different morphologic subtypes of CC. Imaging findings of CC on different modalities are described, focusing on intrahepatic CC. Recently recognized imaging features that carry prognostic significance, such as a worse prognosis in tumors that have more desmoplastic stroma, are detailed. Other benign and malignant entities that should be considered in the differential diagnosis of CC will also be discussed.

Renal Pretransplantation Work-up, Donor, Recipient, Surgical Techniques.

Renal transplant is the single best treatment of end-stage renal disease. Computed tomography (CT) is an excellent method for the evaluation of potential renal donors and recipients. Multiphase CT is particularly useful because of detailed evaluation of the kidneys, including the vascular anatomy and the collecting system. MR imaging has no ionizing radiation, but is limited for stone detection, making it a less preferred method of evaluating donors. Preoperative knowledge of the renal vascular anatomy is essential to minimize risks for donors. Imaging evaluation of recipients is also necessary for vascular assessment and detection of incidental findings.

Imaging spectrum of cholangiocarcinoma: role in diagnosis, staging, and posttreatment evaluation.

Cholangiocarcinoma, a tumor of biliary epithelium, is increasing in incidence. The imaging appearance, behavior, and treatment of cholangiocarcinoma differ according to its location and morphology. Cholangiocarcinoma is usually classified as intrahepatic, perihilar, or distal. The three morphologies are mass-forming, periductal sclerosing, and intraductal growing. As surgical resection is the only cure, prompt diagnosis and accurate staging is crucial. In staging, vascular involvement, longitudinal spread, and lymphadenopathy are important to assess. The role of liver transplantation for unresectable peripheral cholangiocarcinoma will be discussed. Locoregional therapy can extend survival for those with unresectable intrahepatic tumors. The main risk factors predisposing to cholangiocarcinoma are parasitic infections, primary sclerosing cholangitis, choledochal cysts, and viral hepatitis. Several inflammatory conditions can mimic cholangiocarcinoma, including IgG4 disease, sclerosing cholangitis, Mirizzi's syndrome, and recurrent pyogenic cholangitis. The role of PET in diagnosis and staging will also be discussed. Radiologists play a crucial role in diagnosis, staging, and treatment of this disease.