Intravascular large B-cell lymphoma with cutaneous manifestations: a clinicopathologic, immunophenotypic and molecular study of three cases.

Background: Intravascular large B-cell lymphoma (IVLBCL) is an extremely rare type of malignant lymphoma characterized by exclusive or predominant growth of neoplastic cells within the lumen of blood vessels. Cases in the literature predominantly involve the skin and central nervous system, with special emphasis on the 'cutaneous variant'.
Methods: Three cases of IVLBCL with cutaneous manifestations, including two systemic IVLBCL and one cutaneous variant, were described in this study. In all cases, clinical presentation and follow-up data were meticulously evaluated and immunophenotypic and molecular studies were performed.
Results: All three cases displayed the B-cell phenotype and showed monoclonality with immunoglobulin heavy chain gene rearrangement. Bcl2 was expressed in the two systemic IVLBCL cases with fatal outcomes. The third patient with the 'cutaneous variant' achieved complete remission and a longer survival time of 15 months after chemotherapy.
Conclusions: Skin manifestations and neurological findings, although to different degrees, are important clues to the diagnosis of IVLBCL. As most IVLBCL are grouped into the post-germinal center B-cell subtype of diffuse large B-cell lymphoma, Bcl2 expression may be correlated with a worse prognosis in IVLBCL. The cutaneous variant of IVLBCL has a significantly better outcome than that of systemic IVLBCL.