What Is Primary Hepatic Lymphoma?
Primary hepatic lymphoma is an uncommon type of non-Hodgkin's lymphoma. It primarily impacts the liver. Most forms of non-Hodgkin's lymphoma occur in spleen or lymph nodes.
Blood investigations and imaging features cannot confirm the diagnosis. Histopathology helps in the confirmation of diagnosis. Combinations of radiation, chemotherapy, and surgical excision are used as treatment techniques. The prognosis of the condition without any therapy is generally poor.
What Is the Occurrence of Primary Hepatic Lymphoma?
PHL's precise frequency and incidence are unknown. PHL is uncommon; it accounts for 0.4 % of extranodal NHL cases and 0.016 % of NHL cases overall. This condition is more commonly seen in men than women. It is frequently seen in people of age 50.
What Is the Pathophysiology of Primary Hepatic Lymphoma?
The exact cause of primary hepatic lymphoma is unknown. Despite the pathology behind the onset of other forms of lymphoma (Hodgkin’s and non-Hodgkin’s lymphoma) is known. According to recent findings, individuals infected with the hepatitis C virus (HCV) have a higher incidence of PHL. This is because the virus is considered to activate B cells, resulting in the development of polyclonal and, eventually, monoclonal B cells. Likewise, infection with hepatitis B virus (HBV) also stimulates B cell proliferation, leading to the growth of monoclonal B cells.
In some cases, activation of EBV may trigger primary hepatic lymphoma to develop. T lymphocytes normally stop polygonal B cells from proliferating. When immunocompromised patients have impaired T-cell function, EBV leads to uncontrolled polyclonal B-cell proliferation, which may lead to the formation of lymphoma. PHL has also been documented in AIDS (acquired immunodeficiency virus) patients, transplant recipients receiving Cyclosporine therapy, and individuals with systemic lupus erythematosus (an autoimmune condition that damages tissue in the afflicted organs and results in extensive inflammation).
What Are the Clinical Features of Primary Hepatic Lymphoma?
The clinical features of primary hepatic lymphoma include the following:
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Individuals with primary hepatic lymphoma usually experience upper abdomen pain, nausea, vomiting, and jaundice (yellowing of the skin and eyes due to high bilirubin).
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Some individuals may also experience hepatomegaly (enlargement of the liver), which results in discomfort in the abdominal region.
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Many individuals will not recognize the pain or any lump in the right side of their abdomen till the lymphoma grows and impairs the liver capsule.
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Rare symptoms of primary hepatic lymphoma include persistent hepatitis (inflammation of the liver) and abrupt liver failure.
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Due to portal hypertension (high blood pressure in the portal vein) and liver failure, primary hepatic lymphoma can also result in congestive splenomegaly (enlargement of the spleen).
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Sometimes, liver enzymes will be elevated.
What Are the Imaging Characteristics of Primary Hepatic Lymphoma?
The most typical appearance of primary hepatic lymphoma is a single tumor (53 to 65 %). It lacks distinguishing radiographic characteristics and is frequently misdiagnosed as another liver tumor. The most precise method of diagnosis is liver biopsy. Imaging features of various imaging methods are given below:
Ultrasound:
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Ultrasound is the first test involved in the diagnosis of primary hepatic lymphoma. It involves using high-frequency sound waves that help in producing a visualization of the internal structures of the body.
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Generally, hypoechoic (darker than the surrounding tissues) is most likely a result of elevated cellularity and a deficiency of background stroma.
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Occasionally, the tumor may be so hypoechoic that it appears similar to a cyst.
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Also, sometimes, they appear with inner hyperechogenicity (lighter images) and outside hypoechogenicity.
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They may also show enhanced peripheral blood circulation on color Doppler imaging.
Computed Tomography (CT):
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Computed tomography refers to a computerized X-ray imaging method where a narrow beam of radiation is rapidly rotated around the individual’s body. This process produces signals that are interpreted by the machine's computer, which then creates cross-sectional images, or "slices," of the patient's body.
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CT often shows a single solid liver lesion that is hypoattenuating (darker than the surrounding tissue because of hypovascularity), as compared to secondary lymphoma, which can infiltrate more widely.
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Primary hepatic lymphoma varies greatly in size.
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Primary hepatic lymphoma has a predominant mass, whereas secondary lymphatic involvement appears more widespread.
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It appears as a poorly defined mass.
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Sometimes, there will be bleeding, necrosis (death of the tissues), and rim enhancement (the edge of the mass exhibits a more noticeable enhancement).
Magnetic Resonance Imaging (MRI):
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Using radio waves and a strong magnetic field, magnetic resonance imaging (MRI) is a painless, noninvasive medical procedure that creates two- or three-dimensional visualizations of the organs and tissues inside the body.
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On T1-weighted pictures, the typical imaging appearance on magnetic resonance imaging is hypo or isointense, and on T2-weighted images, it is hyperintense. The hypovascularity and ring enhancement may be more clearly seen when gadolinium contrast has been administered.
Positron Emission Tomography–Computed Tomography (PET-CT):
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PET-CT, also referred to as positron emission tomography–computed tomography, is a nuclear medicine technique that incorporates an X-ray computed tomography (CT) scanner and a positron emission tomography (PET) scanner.
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Images are obtained from both the device and superimposed to provide a single image.
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Increased FDG (fluorodeoxyglucose) absorbance is shown in the location of hepatic lesions on PET scan imaging.
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PET scans are also useful in the exclusion of liver secondary lymphomas.
How Is Primary Hepatic Lymphoma Treated?
The foundation of the treatment strategy relies on case reports or short case series because the condition is extremely rare. Options for treatment include radiation, chemotherapy, surgery, and combinations of the aforementioned treatments.
Tumor sizes larger than 2.76 inches, blood lactate dehydrogenase levels higher than ten percent of normal, elevated beta-2 microglobulin levels greater than 3 mg/dl, and the existence of constitutional symptoms are some risk factors that influence prognosis and responsiveness to treatment.
Combination chemotherapy with Doxorubicin, Vincristine, Cyclophosphamide, and Prednisone is effective in individuals without any risk factors. Employing a modified triple combination needs to be considered for patients who have one or more risk factors. Methotrexate, Bleomycin, Cyclophosphamide, Doxorubicin, Vincristine, and Methylprednisolone alternate with Doxorubicin, Methylprednisolone, Cytosine arabinoside, and Cisplatin in alternative regimens.
What Is the Prognosis of Primary Hepatic Lymphoma?
Combination chemotherapy is effective in treating primary hepatic lymphoma, with over 80 % of patients experiencing a full recovery. The outlook following the surgery generally varies. This is because of the vascular nature of the primary hepatic lymphoma. It increases the chance of bleeding during surgery, which increases the rate of morbidity and death.
Conclusion:
Primary hepatic lymphoma is a rare form of non-Hodgkin’s lymphoma. The specific diagnosis of the condition is quite difficult because of its resemblance with other liver conditions. The treatment methods include chemotherapy, radiation, surgery, and a combination of the above. If individuals experience any symptoms related to the condition, consult a physician to make a definitive diagnosis and determine a proper treatment plan on time.
