We report a unique, previously undescribed case of KSHV/HHV8-associated lymphoma in a 49-year-old HIV-seropositive patient. The cervical lymph node-based lymphoma displayed distinctive characteristic features of preferential sinusoidal infiltrate and anaplastic cellular morphology, closely resembling classic anaplastic large cell lymphoma of the WHO classification both histologically and immunophenotypically. Paraffin immunohistochemical study showed that the lymphoma cells were strongly positive for KSHV/HHV8 latency-associated nuclear antigen, and PCR analysis confirmed the presence of KSHV/HHV8 infection. Epstein-Barr virus in situ hybridization was negative. Molecular study clearly demonstrated B-cell lineage with immunoglobulin heavy and kappa light chain gene rearrangements. This case may add to the spectrum of the heterogeneous category of KSHV/HHV8-associated B-cell lymphomas.