Intravascular lymphoma presenting with bone marrow involvement and leukemic phase

Area of Science:

• Hematology
• Oncology
• Immunophenotyping

Background:

• Intravascular lymphoma (IVL) is a rare non-Hodgkin lymphoma characterized by proliferation of malignant lymphocytes within blood vessels.
• Diagnosis can be challenging due to nonspecific symptoms and the absence of a distinct tumor mass.
• Peripheral blood and bone marrow involvement are considered uncommon in IVL, often leading to delayed or missed diagnoses.

Observation:

• A 62-year-old male presented with constitutional symptoms and cognitive decline.
• Initial peripheral blood examination revealed pancytopenia with blast-like cells.
• Bone marrow biopsy showed extensive infiltration by vacuolated, blast-like cells, initially suggesting Burkitt's leukemia/lymphoma.

Findings:

• Immunophenotyping identified the abnormal cells as CD5-positive mature B-cells, prompting re-evaluation of the initial diagnosis.
• Confirmation of a sinusoidal pattern by immunocytochemistry was crucial for revising the diagnosis to intravascular lymphoma (IVL).
• Literature review suggests that peripheral blood and bone marrow involvement in IVL, though rare, may be under-recognized due to infrequent systematic investigation.

Implications:

• This case highlights the importance of considering IVL in the differential diagnosis of unexplained constitutional symptoms and hematologic abnormalities.
• The presence of CD5 expression on malignant cells in IVL, while increasingly reported, requires further investigation to determine its frequency and clinical significance.
• Systematic evaluation of peripheral blood and bone marrow may improve the detection rates of IVL, potentially leading to earlier treatment and better patient outcomes.