Background
Liver is the largest reticuloendothelial organ which is involved in many hematologic malignancies. Liver is one of the extranodal site of non-Hodgkins lymphoma.
Hepatic lymphoma can be classified into primary and secondary forms. Primary hepatic lymphoma (PHL) is a rare form of non-Hodgkin lymphoma (NHL) which is confined to liver and hilar lymph nodes and accounts for <1% of all NHL cases. In contrast, multifocal lesions or diffuse infiltration is the commonest pattern of secondary hepatic lymphoma
Involvement of liver secondary to systemic NHL is seen in 40% of patients.
Diagnosis of PHL depends on a liver biopsy that is compatible with the lymphoma and the absence of extrahepatic lymphoproliferative involvement.
Clinical Perspective
Clinical presentation is variable ranging from fulminant onset of disease to death[1]. The common presenting symptom is right upper quadrant pain, jaundice, weight loss, and fever [2]. Secondary hepatic lymphoma presents with systemic symptoms like fever, night sweats and weight loss along with hepatosplenomegaly and generalised lymphadenopathy.
Lei et al. [3] proposed the following diagnostic criteria for PHL: symptoms at presentation caused mainly by liver involvement, absence of both clinical and radiological distant lymphadenopathy, and absence of leukemic blood involvement in the peripheral blood smear.
Laboratory findings associated with PHL include abnormal liver tests results, with nonspecific elevations of AST, alanine aminotransferase, alkaline phosphatase, and bilirubin levels. LDH elevation is common, being present in 30–80% of patients. Tumour markers such as AFP, CA 19-9, and CEA are within normal range in almost 100% of cases, helping to differentiate PHL from hepatocellular carcinoma or metastatic disease.
Imaging Perspective
Radiologically, hepatic lymphoma can present in three forms:
- Solitary lesion
- Multifocal lesions
- Diffuse hepatic infiltration
Periportal mass can be seen in both primary and secondary hepatic lymphoma
At CT, periportal mass type of hepatic lymphoma shows ill-defined hypoenhancing soft tissue mass encasing portal and bilary tracts without causing its obstruction (vessel penetration sign).
At MR imaging, the lesion tend to be hypo- or isointense on T1-weighted images and moderately hyperintense on T2-weighted images with diffusion restriction.
Take-Home Message
PHL is an exceedingly rare disease, having no pathognomonic imaging/clinical features. It should be part of the differential diagnosis in a patient presenting with nodular/diffuse hepatic lesions, especially in the presence of normal tumour markers and/or elevated LDH levels/history of immunosuppression. Histology is mandatory for definitive diagnosis. It is important to recognize PHL because it is a chemosensitive disorder, allowing early treatment and improved overall prognosis.
