Primary hepatic lymphoma (PHL) is a rare, malignant lymphoma of the liver. It differs from the predominantly lymph nodal or splenic involvement associated with other types of lymphoma. It is usually detected incidentally on imaging examination, commonly computed tomography (CT), for nonspecific clinical presentation. However, it has important clinical implications for early diagnosis and treatment as indicated in our case.
Case Presentation
An 84-year-old man presented to the emergency department for evaluation of upper back pain. The patient had a history of hypertension, diabetes mellitus, and was a former smoker. He had normal vital signs, an unremarkable physical examination, and a body mass index of 25. His laboratory studies showed a normal blood cell count and serum chemistry, including serum calcium level and α-fetoprotein, but mildly elevated liver function tests.
The patient’s chest CT angiography showed no evidence of thoracic aortic dissection, penetrating atherosclerotic ulceration, or pulmonary artery embolism. Besides emphysematous changes in the lung, the chest CT was within normal limits.
Abdominal magnetic resonance imaging (MRI) showed hepatomegaly (the liver measured up to 19.3 cm in craniocaudal length) and multiple, large intrahepatic space-occupying lesions, the largest measuring 9.9 cm × 9.5 cm in the right lobe, as well as multiple lesions in the inferior right and left lobe with enhancing capsules surrounding the hepatic lesions (Figure 2).
An ultrasound-guided core needle biopsy of the liver was performed. Flow cytometry showed a monoclonal B-cell population that was mostly intermediate to large based on forward scattered light characteristics. Immunohistochemical staining was positive for CD20, BCL2, BCL6, and CD45 in the neoplastic cells. Anaplastic lymphoma kinase (ALK), CD15, CD30, and CD10 were negative, as were cytokeratin AE1/AE3 and pan-melanoma. CD3 highlighted background T cells. Ki-67 highlighted a proliferative index of approximately 75%, and the MYC stain demonstrated 50% positivity. This was consistent with diffuse large B-cell lymphoma (DLBCL). However, there was insufficient tissue on the MUM1-stained slide; therefore, it was inconclusive to distinguish a nongerminal center derived from germinal center–derived DLBCL.
Two weeks after the initial CT examination, the patient’s condition quickly deteriorated, and he was admitted for severe weakness with evidence of severe hypercalcemia, hyperuricemia, and renal insufficiency (Table).
To get additional tissue for further tumor characterization, a repeat liver biopsy was performed along with other diagnostic tests, including head MRI, bone marrow biopsy, and fluorodeoxyglucose (FDG) full-body positron emission tomography (PET). Repeat liver biopsy showed only necrotic debris with immunostaining positive for CD20 and negative for CD3. B-cell lymphomas tend to retain CD20 expression after necrosis, so the presence of CD20 staining was consistent with a necrotic tumor. Again, there was insufficient tissue on the MUM1-stained slide. Head MRI showed no evidence of tumor involvement. Full-body PET showed abnormally elevated standardized uptake value (SUV) of radioactive tracers in several areas: multifocal, large area uptake within both right (SUV, 19) and left (SUV, 24) hepatic lobe (Figure 3A), retroperitoneal lymph node (SUV, 3.9), and a right lateral pleural-based nodule (SUV, 17.9) (Figure 3B).
The diagnosis was primary DLBCL of the liver with retroperitoneal lymph nodes and right lung metastasis. The patient was started on systemic chemotherapy of R-CHOP (rituximab with reduced cyclophosphamide, doxorubicin, vincristine, and prednisone).