intravascular large B-cell lymphoma

Epidemiology

• rare

Pathology

• extranodal lymphoma
• accumulation of large neoplastic B cells within the lumina of blood vessels
• 3 variants
  • classic variant
    • skin & central nervous system most frequently involved
    • lung, kidney, liver, adrenals may be involved
  • hemophagocytic syndrome-associated variant
    • fever, thrombocytopenia, splenomegaly, bone marrow involvement
  • cutaneous variant
    • cutaneous lesions without additional sites of involvement (25%)
    • best prognosis

Microscopic pathology

• large round cells with scant cytoplasm & prominent nucleoli proliferating within blood vessels

Immunophenotype

• CD20 +, +, Bcl-6 +, cMYC +, multiple myeloma 1 +
• Ki-67 staining index ~90%
• endothelial cells of the involved vessels CD34 +, CD31 +, D2-40 (-) Clinical manifstations:
• indurated violaceous plaques with multiple telangiectasias on lower limbs most common with cutaneous variant
• ulceration, orange peel appearance, panniculitis-like lesions, palpable purpura, retiform purpura, & cherry angiomas may be noted

Radiology

• PET scan;
  • no lymphadenopathy or metastases*
  • no evidence of bone marrow involvement*

* cutaneous variant

Differential diagnosis

• intralymphatic histiocytosis
• reactive angioendotheliomatosis
• intralymphatic proliferation of T-cell lymphoblasts (CD30+)

Management

• 6 cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, & prednisone (R-CHOP)

More general terms

• peripheral B-cell lymphoid neoplasm
• large cell lymphoma

Additional terms

• diffuse large B-cell lymphoma (DLBCL)