Unusual variants of intravascular malignant hematopoietic neoplasms: a report of 4 cases and review of the literature.

Intravascular lymphoma (IVL) is a rare and fatal disease, typically of B-cell origin. Most of the reported cases have been for primary IVL, and only a minority of cases are of recurrent IVL. In addition, recurrent IVL occurring after treatment of anaplastic large T-cell lymphoma (ALCL) by contrast is extraordinarily rare. In this article, we present 3 cases of recurrent cutaneous IVL (2 men and 1 woman) and compare these with 1 case of primary IVL. The patients ranged in age from 56 to 73 years and were encountered in the routine dermatopathology and consultative practices of one of the authors. In 2 of the cases, the patients had intravascular cutaneous ALCL. In regard to the remaining 2 patients, 1 patient had a recurrent intravascular cutaneous follicular lymphoma in the context of a history of diffuse large B-cell lymphoma. The fourth patient had a primary intravascular ALCL because there was no antecedent history. In all cases, the skin biopsies showed large aggregates of atypical cells within the blood vessels. Phenotypic studies revealed variable staining results with CD29 and CD54 in cases of recurrent IVL compared with those of primary IVL. Recurrent cutaneous IVL represents a somewhat heterogeneous group of lymphoproliferative disorders with a distinct variant being in the context of intravascular ALCL; the mechanisms of intravascular localization in recurrent IVL are likely different from those of primary IVL.