Diagnosis of Benign Liver Tumors
Clinical symptoms and patient history are crucial in determining the extent of the diagnostic workup. The diagnostic challenge is to distinguish between three types of lesions: tumors that must be removed, tumors that should be monitored, and tumors that may be ignored.
Symptomatic Patients In cases of pain or severe discomfort, the first step is to ensure these symptoms are related to the liver mass and to evaluate the severity of these symptoms, considering the psychological effect of the diagnosis of a liver tumor. Symptoms are usually related to large cysts, or necrotic/hemorrhagic adenomas. It is an exceptional case when focal nodular hyperplasia or hemangiomas cause symptoms. If the tumor is indeed symptomatic, surgical resection is most likely indicated, so that the preoperative diagnostic workup can be shortened—as histology will unlikely influence the decision. In cases of hemorrhagic or ruptured tumors, imaging investigations are less diagnostic than strategic, the goal being to plan the surgical procedure.
Asymptomatic Patient Incidentalomas are increasingly frequent because of the development of imaging modalities. A common clinical discovery involves one or several focal lesions on an ultrasound (US) or computed tomography (CT) scan performed for reasons unrelated to the liver. Usually, the patient is a young woman, and the focal lesion is small. In other cases, the presentation is different; the tumor is large and multiple, and sometimes, different types of focal lesions are described.
The clinical interview should address the personal or familial history of malignancy and age-appropriate screening, past history of hepatitis or blood transfusions or intravenous drug use, and estrogen or progesterone use. Liver biochemistry (usually normal in cases of benign, uncomplicated tumors), viral serologies, and tumor markers are useful for excluding liver disease or with atypical presentations.
The diagnostic tools in this field principally involve US, contrast-enhanced CT scan, and magnetic resonance imaging (MRI).
Ultrasound is usually the first investigation that detects the focal mass. It is a simple and noninvasive technique to differentiate solid from cystic lesions and may be sufficient to establish the diagnosis of small hemangiomas or hepatic cysts. However, the diagnostic specificity for solid lesions is low even when improved by the use of color-flow Doppler or contrast US, which may add dynamic information regarding the lesions. Tripe-phase CT is an excellent modality for characterizing lesions, yielding specific signs in cases of large hemangiomas or FNH, but in many cases, this single modality is not sufficient for establishing the correct diagnosis. Magnetic resonance imaging is the best imaging modality in terms of specificity for diagnosing hepatic lesions, particularly when liver-specific contrast agents are utilized. Usually, a combination of these exams provides sufficient clues to establish a definitive diagnosis. Positron emission tomography (PET), sulfur colloid, tagged red blood cells, and other modalities have been infrequently used, and their role requires further evaluation.
In symptomatic patients exhibiting acute signs due to hemorrhage, tumor necrosis, or experiencing discomfort caused by mass effects and compressive phenomena, a diagnostic workup is useful less for the decision to go to surgery than to determine the strategy that will allow for an adequate and safe surgical approach. In these cases, a CT scan is the standard. Generally, the combination of the clinical presentation, medical history, and CT scan renders the diagnosis obvious. For example, a young woman who presents with hemorrhagic solid lesions like suffers from adenoma, whereas a large cyst with dense, layering components has hemorrhaged into a simple cyst. If the clinical or radiological presentation is unusual, the differential diagnosis includes different considerations. For solid lesions, HCC, fibrolamellar carcinoma, choriocarcinoma, or rare metastatic hypervascularized tumors (endocrine, breast metastasis, etc.) should be considered. For cystic lesions, hydatid cysts, cystadenocarcinoma, or cystic metastasis (gastrointestinal stromal tumors, endocrine tumors, etc.) should be considered. Male sex, severe pain, systemic symptoms, or abnormal liver biochemistry should increase the suspicion of malignancy and lead to further investigation.
For asymptomatic tumors, a combination of two to three imaging modalities usually makes the diagnosis: in greater than 70% of cases, a diagnosis of hemangioma, FNH, or hepatic cyst may be achieved with these noninvasive modalities (Table 2). Otherwise, a radiologist may suggest an atypical FNH or adenoma, or rare tumors such as angiomyolipomas, focal fatty nodules, pseudotumors, or granulomas because of nonspecific signs or because the suspected tumor is exceedingly rare.
In cases with an uncertain diagnosis or a neoplastic history, histological analysis is mandatory; thus, image-guided or laparoscopic biopsy, or operative resection should be considered.
Semin Liver Dis. 2013;33(3):236-247. © 2013 Thieme Medical Publishers