Fulminant Mantle Cell Lymphoma Presenting With Hepatic Infiltration and Spontaneous Tumor Lysis Syndrome.

Mantle cell lymphoma (MCL) is an uncommon, aggressive B-cell non-Hodgkin lymphoma that typically presents with lymphadenopathy, splenomegaly, and gastrointestinal (GI) tract involvement, most often as multiple lymphomatous polyps. While hepatic involvement by MCL is rare and usually asymptomatic, hepatic lesions in clinical practice more often represent metastases from GI, breast, lung, or pancreatic primaries. We report a case of MCL initially presenting with tumor lysis syndrome (TLS) and cholestatic liver injury, mimicking hepatobiliary malignancy. A 90-year-old male with coronary artery disease complicated by coronary artery bypass grafting presented with abdominal pain, nausea, and vomiting. He was initially discharged with a presumed diagnosis of chronic lymphocytic leukemia based on the complete blood count. He re-presented several days later with worsening jaundice, anorexia, weakness, and a shuffling gait. Laboratory evaluation revealed leukocytosis, an acute kidney injury, hyperkalemia, hyperuricemia, hyperammonemia, and a cholestatic pattern of liver injury. Cross-sectional imaging demonstrated hepatosplenomegaly, multifocal splenic infarcts, gallbladder wall thickening with cholelithiasis, and no biliary ductal dilation. Bone marrow flow cytometry revealed a CD5+ (bright), CD23+, FMC7+, CD10-, kappa-restricted mature B-cell population consistent with MCL. Liver biopsy confirmed diffuse hepatic infiltration by MCL with a high proliferative index (Ki-67: 70-80%). Given the presentation of spontaneous TLS, the patient was admitted to the intensive care unit for vasopressors, continuous renal replacement therapy, and rasburicase. Given poor functional status, curative therapy was deferred, and palliative care was initiated. The patient ultimately passed away from multi-organ failure. This case underscores the importance of considering infiltrative lymphoma in patients presenting with hepatosplenomegaly, atypical cholestasis, and no clear obstructive process. Early liver biopsy can be pivotal in differentiating hematologic malignancy from primary hepatobiliary carcinoma when imaging is inconclusive. Although hepatic MCL is rare, it can present with fulminant disease and spontaneous TLS. Timely recognition may expedite diagnosis and guide appropriate management, especially in elderly or frail patients where treatment must be individualized.