Makindo Medical Notes

Related Subjects: |Hodgkin Lymphoma |Non Hodgkin Lymphoma |Diffuse large B-cell lymphoma |Intravascular large B-cell lymphoma |Mantle cell lymphoma |Marginal Zone Lymphoma |Gastric (MALT) Lymphoma |Primary CNS Lymphoma (PCNSL) |Burkitt's lymphoma |Follicular Lymphoma

🩸 Intravascular Large B-Cell Lymphoma (IVLBCL) is a rare, aggressive subtype of extranodal non-Hodgkin lymphoma. It is characterized by the selective proliferation of malignant B-cells within the lumina of small to medium-sized vessels, without forming a distinct tumor mass. ⚠️ Because of its protean manifestations and lack of obvious masses, IVLBCL is frequently misdiagnosed or discovered only at post-mortem.

ℹ️ About

• Selective intravascular growth of malignant lymphocytes obstructing blood vessels. 🧬
• Absence of a discrete mass makes diagnosis particularly challenging.
• Belongs to the spectrum of diffuse large B-cell lymphomas (DLBCL).

🧬 Aetiology & Epidemiology

• A rare subtype of extranodal DLBCL.
• Some cases are EBV-associated (especially in immunosuppressed patients).
• Organ involvement: CNS (≈60%), skin (≈7%), bone marrow/spleen (≈11%), lungs (≈7%).
• Two major clinicopathologic variants: • Western type: CNS and skin predominant involvement. • Asian type: Haemophagocytic syndrome with fever, cytopenias, hepatosplenomegaly, and marrow involvement.

👩‍⚕️ Clinical Features

• Occurs mainly in the elderly.
• 🧑‍⚕️ Cutaneous findings: Rashes, plaques, or nodules mimicking vasculitis or panniculitis.
• 🧠 CNS disease: Encephalopathy, strokes, seizures, focal neurological deficits due to vascular occlusion.
• 🩺 Systemic: Splenomegaly, fever, B-symptoms, cytopenias.
• Asian variant: often with haemophagocytic syndrome (fever + splenomegaly + cytopenias).
• Can masquerade as infection, vasculitis, or thromboembolic disease.

🧪 Investigations

• FBC: Normocytic anaemia, thrombocytopenia; markedly raised LDH and CRP. 📈
• Skin biopsy: Demonstrates vascular occlusion by large CD20+ B-cells.
• PET-CT: Shows patchy uptake in lung, marrow, renal cortex, or CNS, though absence of a mass is typical.
• Flow cytometry: May show a clonal B-cell population in blood/marrow.
• Lumbar puncture: CSF often negative despite CNS involvement.
• CXR: Usually unremarkable despite systemic illness.

🧫 Pathology

• Neoplastic B-cells confined to vessel lumina, obstructing small capillaries/venules. 🩸
• Cells strongly express CD20 and other pan-B markers (e.g., CD79a, PAX5).
• Histology lacks parenchymal infiltration or nodal involvement in most cases.

💊 Management

• ⚠️ IVLBCL is highly aggressive with poor prognosis if untreated; many diagnoses occur post mortem.
• Systemic chemotherapy: CHOP-based regimens combined with Rituximab (R-CHOP) improve outcomes significantly.
• CNS-directed therapy: Intrathecal methotrexate ± high-dose systemic methotrexate, due to high CNS relapse risk. 🧠
• Supportive care: Manage cytopenias, coagulopathy, infections, and organ failure.
• Early recognition and biopsy (skin or marrow) are critical to survival.

📚 References

• Intravascular Large B-Cell Lymphoma: Clinical and Histopathologic Findings – PMC
• Blood Journal Review: IVLBCL – An Elusive Diagnosis