Human herpesvirus 8-associated lymphoma mimicking cutaneous anaplastic large T-cell lymphoma in a patient with human immunodeficiency virus infection.

Primary effusion lymphoma, a human herpesvirus 8 (HHV8)-associated lymphoma, is uncommon, and it is usually seen in human immunodeficiency virus (HIV)-infected patients. It presents as a body cavity-based lymphomatous effusion, but several cases of the so-called solid primary effusion lymphoma presenting as solid tumors without associated lymphomatous effusion have been reported. They have similar clinical, histopathological and immunophenotypical features. Most of them have a B-cell genotype. This suggests the solid variant may represent a clinicopathological spectrum of primary effusion lymphoma. We report a case of HHV8-associated lymphoma histopathologically and immunophenotypically mimicking cutaneous anaplastic large cell lymphoma. The patient was a 31-year-old HIV-seropositive man presenting with skin nodules over his right thigh. Biopsy of the nodules showed anaplastic large cells infiltrating the dermis. These malignant cells strongly expressed CD3, CD30 and CD43. Cutaneous anaplastic large T-cell lymphoma was initially diagnosed, but further tests, including immunoreactivity for HHV8 protein and clonal rearrangements of immunoglobulin genes, confirmed the diagnosis of HHV8-associated B-cell lymphoma with aberrant T-cell marker expression. This case provides an example of solid primary effusion lymphoma mimicking cutaneous anaplastic large T-cell lymphoma and highlights the importance of HHV8 immunohistochemistry and molecular tests in the diagnosis of HHV8-associated lymphoma with a cutaneous presentation.