The Diagnosis and Management of Benign Hepatic Tumors :

Cystic lesions of the liver in the adult can be classified as developmental, neoplastic, inflammatory, or miscellaneous. Although in some cases it is difficult to distinguish these entities with imaging criteria alone, certain cystic focal liver lesions have classic computed tomographic (CT) and magnetic resonance (MR) imaging features, which are important for the radiologist to understand and recognize. Lesions with such features include simple (bile duct) cyst, autosomal dominant polycystic liver disease, biliary hamartoma, Caroli disease, undifferentiated (embryonal) sarcoma, biliary cystadenoma and cystadenocarcinoma, cystic subtypes of primary liver neoplasms, cystic metastases, pyogenic and amebic abscesses, intrahepatic hydatid cyst, extrapancreatic pseudocyst, and intrahepatic hematoma and biloma. Specific CT and MR imaging findings that are important to recognize are the size of the lesion; the presence and thickness of a wall; the presence of septa, calcifications, or internal nodules; the enhancement pattern; the MR cholangiographic appearance; and the signal intensity spectrum. In addition, access to critical clinical information remains extremely important. The most important clinical parameters defined include age and gender, clinical history, and symptoms. An understanding of the classic CT and MR imaging appearances of cystic focal liver lesions will allow more definitive diagnosis and shorten the diagnostic work-up.

Focal nodular hyperplasia (FNH) is the second most common benign liver tumor after hemangioma. FNH is classified into two types: classic (80% of cases) and nonclassic (20%). Distinction between FNH and other hypervascular liver lesions such as hepatocellular adenoma, hepatocellular carcinoma, and hypervascular metastases is critical to ensure proper treatment. An asymptomatic patient with FNH does not require biopsy or surgery. Magnetic resonance (MR) imaging has higher sensitivity and specificity for FNH than does ultrasonography or computed tomography. Typically, FNH is iso- or hypointense on T1-weighted images, is slightly hyper- or isointense on T2-weighted images, and has a hyperintense central scar on T2-weighted images. FNH demonstrates intense homogeneous enhancement during the arterial phase of gadolinium-enhanced imaging and enhancement of the central scar during later phases. Familiarity with the proper MR imaging technique and the spectrum of MR imaging findings is essential for correct diagnosis of FNH. Copyright RSNA, 2004

Hepatic hemangiomas are congenital vascular malformations and are the most common benign hepatic tumors. Because the use of cross-sectional imaging has increased, benign hepatic tumors, especially hemangiomas, are encountered more frequently, so clinicians should be familiar with the most appropriate diagnostic tests, management, and outcomes of patients with hepatic hemangioma. All patients with a primary diagnosis of hepatic hemangioma referred for surgical evaluation at our institution between January 1992 and December 2000 were identified from a prospective database. Demographics, presentation, tumor characteristics, diagnostic studies, surgical procedures, and outcomes were analyzed. RESULTS; Of 115 patients in the study, nearly half were asymptomatic. In symptomatic patients, abdominal pain or discomfort was the most common presenting symptom. At our institution, the diagnosis of hemangioma was established by ultrasonographic studies in 57% of patients tested, by CT scan in 73%, and by MRI in 84%. In patients with large tumors considered for resection, direct angiography or, more recently, CT angiography, confirmed the diagnosis in 27 of 29 patients (93%). Enucleation was performed in 31 (60%) of the 52 patients who underwent surgical resection; 63 patients were observed. Postoperative complications occurred in 13 patients (25%), and there were no perioperative deaths. Of the patients with symptoms before resection, 96% had resolution of symptoms after operation. Hepatic hemangioma can be diagnosed in most patients using noninvasive studies, particularly MRI. Hepatic hemangiomas can be removed safely if patients become symptomatic or when malignancy cannot be excluded. CT angiography can be a valuable preoperative study in patients with large tumors, and enucleation is the procedure of choice. In asymptomatic or minimally symptomatic patients, hepatic hemangiomas usually have a benign course and can be observed.