primary hepatic lymphoma

Primary

hepatic mucosa-associated lymphoid tissue lymphoma: a case report and literature review. Computed tomography findings. a Dynamic computed tomography with drip infusion cholangiography revealed focal dilatation of the biliary ducts (arrow) and atrophy (arrowheads) in the posterior segments of the liver. b No tumor was detected via enhanced computed tomography

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Primary

hepatic mucosa-associated lymphoid tissue lymphoma: a case report and literature review. Enhanced magnetic resonance imaging after gadolinium injection. The tumor was hyper-intense on T1-weighted images (arrow) in the area adjacent to the main posterior biliary duct in the arterial phase but showed rapid washout in the late phase

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Primary hepatic lymphoma (PHL) is rare, with roughly 100 described cases. If it is being considered as a diagnosis, distal lymphadenopathy, splenomegaly, bone marrow disease, and leukemia should not be present for at least 6 months after the liver tumor is detected (see: secondary hepatic lymphoma) .

Epidemiology

Rare presentation of lymphoma (<1% of all Non-Hodgkin lymphomas).

In contrast, according to one source, diffuse large B-cell lymphoma (DLBCL) affects around 7 out of 100,000 people annually in the United States, with potential for secondary involvement of the liver, so this is a much more common cause of hepatic lymphoma.

Clinical presentation

The most common presentation includes abdominal pain, jaundice, and weight loss. Although the majority of patients will have elevated liver enzymes, these may be normal. The typical age of presentation is around the age of 55. It has a male preponderance.

Pathology

The exact cause of this primary hepatic lymphoma is still unclear, however, it is primarily found in immunocompromised patients such as AIDS/HIV, congenital immunodeficiency, immunosuppressant therapy for organ transplant and collagen vascular disease. Reports have also shown infections as a cause such as EBV, HIV, hepatitis C and hepatitis B with chronic hepatitis and cirrhosis.

The majority of cases of primary liver lymphoma are diffuse large B-cell lymphoma. Other histologic types include peripheral T-cell leukemia/lymphoma-not-otherwise-specified, follicular lymphoma, mantle cell lymphoma, or Burkitt lymphoma.

Radiographic features

Primary hepatic lymphoma is most commonly seen as a solitary mass (53-65%). PHL does not have characteristic radiographic features and can often be mistaken for other liver tumors. Liver biopsy is the most specific way of making the diagnosis.

Ultrasound

Ultrasound is usually the initial radiological test performed:

typically hypoechoic to the liver parenchyma, probably due to high cellularity and lack of background stroma
rarely, they may be so hypoechoic that they may appear similar to a cyst
occasionally have a "target" appearance with a central hyperechogenicity and outer hypoechogenicity
increased peripheral vascularity with color Doppler

CT

frequently a single (~60%), solid, hypoattenuating (due to hypovascularity) lesion as opposed to secondary lymphoma which can be more diffusely infiltrating
there can be a large variation in size, but PHL tends to have dominant masses, as opposed to secondary lymphomatous involvement of the liver, which tends to be more diffuse
variable contrast enhancement on CT, but tend to be hypoenhancing relative to liver on all phases, with no enhancement in some cases
an ill-defined mass at the porta hepatis is possible
hemorrhage, necrosis, and rim-enhancement are possible

MRI

MRI findings depend on the extent of infiltration.

T1: typically hypointense relative to remainder of liver
T2: often shows variable intensity
T1 C+ (Gd): there is poor gadolinium enhancement of these lesions, but they may show faint peripheral rim enhancement
DWI/ADC: restricts diffusion

Signal characteristics are almost identical to secondary lymphomatous involvement but manifestation as a single solid mass may favor towards a primary hepatic lymphoma .

Nuclear medicine

PET/CT

PET/CT is useful in making the diagnosis and can also be used for staging.

FDG-PET
- avid FDG uptake of the lymphomatous mass in the liver
- can show or exclude extrahepatic sites of lymphoma with a high degree of sensitivity

Treatment and prognosis

PHL is primarily treated with chemotherapy. The most common chemotherapy regimen for advanced diffuse large B-cell lymphoma (DLBCL) is called R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). In the United States, this regimen is generally given every three weeks for 6 to 8 cycles. Other treatment options include radiation therapy or surgery.