A Rare Case Report of Primary Hepatic Lymphoma Complicated by Hemophagocytic Lymphohistiocytosis.

Primary hepatic lymphoma (PHL) is a rare disease characterized by non-specific clinical manifestations, laboratory findings, and imaging features, which may lead to misdiagnosis as hepatocellular carcinoma or hepatic infectious lesions. However, whether PHL can secondarily develop hemophagocytic lymphohistiocytosis (HLH) like other hematological lymphomas has not been reported. We present a diagnostically challenging case initially mimicking a pyogenic liver abscess. A 74-year-old woman with no history of past illness was admitted with persistent high fever accompanied by fatigue and loss of appetite for three weeks. Her vital signs were normal on physical examination. Computed tomography (CT), magnetic resonance imaging, and fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT showed a liver infectious lesion as a hepatic abscess. A subsequent laparoscopic exploration and liver biopsy confirmed the diagnosis of germinal center B-cell-like diffuse large B-cell lymphoma. Concurrently, with the progressive thrombocytopenia and hemoglobin reduction alongside persistent fever, the life-threatening complication of HLH secondary to PHL was reported by the further workup per the HLH-2004 criteria. The modified R-ECHOP chemotherapy regimen was initiated to address both conditions. During follow-up evaluations, significant myelosuppression was identified. The second-cycle chemotherapy regimen was modified to the R-miniCHOP protocol. After four cycles of chemotherapy, the follow-up 18F-FDG PET/CT scan indicated complete response of the liver tumor lesions. In conclusion, PHL is rare and frequently clinically mistaken for a liver abscess. Histopathological examination remains the gold standard for definitive diagnosis. Similar to other hematological lymphomas, PHL may also secondarily develop HLH. Early recognition, diagnosis, and intervention are critical to improving prognosis.