Liver metastasis develops due to the spread of malignant tumors from their primary sites in the gastrointestinal tract, breast, lung, and pancreas. The extension of melanomas and neuroendocrine tumors may also result in this disease. Clinical manifestations can be non-specific and imaging studies like ultrasonography, computed tomograms, and magnetic resonance imaging are required to detect the disease while biopsy with histopathology is necessary to confirm the diagnosis.
Liver metastasis occurs secondary to the spread of melanomas, renal cell carcinoma, neuroendocrine tumors and the primary cancers involving various sites of the body. Of these, the commonest is the colon, followed by non-colorectal locations such as breast, lungs, pancreas, etc. . 95% of uveal melanomas metastasize to the liver versus 15% of cutaneous melanomas     and liver metastasis has been reported in approximately 44% of neuroendocrine tumors   .
In a majority of the patients, the metastases are multiple with concomitant spread to other sites   while a small percentage of patients develop solitary lesions. 75% of the patients have involvement of bilateral lobes of the liver. The incidence and pattern of the metastases depend on the age, sex, primary site of the tumor, duration, and histopathology. Primary liver cancer is less common as compared to liver metastasis.
In the initial stages of the disease, patients with liver metastasis are asymptomatic. Subsequently, they develop non-specific symptoms like anorexia, weight loss, fever, night sweats, cachexia and right upper quadrant pain. On palpation, hard, tender hepatomegaly may be noted. Jaundice is rare in the early stages and is typically seen in the presence of bile duct obstruction. Ascites develops with peritoneal seeding of the tumor and in advanced stages, there is hyperbilirubinemia with hepatic encephalopathy.
Patients with a primary cancer are suspected of having liver metastasis if they present with weight loss and a palpable, enlarged and hard liver. Routine laboratory tests like a complete blood count and liver function tests may be inconclusive in the early stages although alkaline phosphatase, gamma-glutamyl transpeptidase, and lactate dehydrogenase levels may be elevated.
Plain X-ray chest is performed as a routine in patients with a known primary cancer to exclude pulmonary lesions.
Radiological tests such as ultrasonography, computed tomogram (CT) and magnetic resonance imaging (MRI) are required to detect the metastasis. CT with contrast is the study of choice to diagnose the disease with MRI being more sensitive as compared to CT and positron emission tomography (PET) . However, Kinkel et al, have reported that fluorodeoxyglucose (FDG) PET scan is the most sensitive imaging modality to detect liver metastases, especially if the primary tumor is located in the colon, and upper gastrointestinal tract . Liver angiography is indicated in vascular metastasis, especially if, embolization is being considered as a therapeutic modality.
Histopathological evaluation of a liver biopsy specimen obtained under image guidance is usually required for confirmation of the diagnosis.