A challenging case of intravascular large B-cell lymphoma presenting as pyrexia of unknown origin

Abstract

Abstract Introduction: Intravascular large B-cell lymphoma (IVLBCL) is a rare subtype of large cell lymphoma, characterized by the growth of neoplastic cells within the lumina of small blood vessels, without an obvious extravascular tumor mass or presence of circulating lymphoma cells in the peripheral blood. Patient concern: A 68-year-old woman presented with fever of unknown origin and abdominal pain. Diagnosis: Bone marrow aspiration showed abnormally large cells with increased hemophagocytic activity. Trephine biopsy showed moderate to large neoplastic cells with single and multiple prominent nucleoli sequestered in the blood vessel lumen. Immunohistochemistry was positive for CD20, PAX5, CD79a, MUM1, and BCL2 and showed a high proliferative fraction of 80% confirming the diagnosis of IVLBCL. Interventions: The patient received six cycles of R-CHOP chemotherapy. Outcomes: The patient has been in remission for nearly two years after completing the treatment. Conclusion: Clinical recognition of IVLBCL remains a challenge. Standard staging and therapeutic approaches need to be addressed to further elucidate the characterization and management of this rare disease.