Senile EBV‐associated B‐cell lymphoproliferative disorder of indolent clinical phenotype with recurrence as aggressive lymphoma

Senile EBV‐associated B‐cell lymphoproliferative disorder (LPD) was proposed as a new disease entity in 2003. This condition has a high incidence in elderly people without underlying immunodeficiencies, and is characterized by EBV‐positive B‐cell proliferation with a polymorphic composition. Histologically, the disease has two subtypes. The polymorphic LPD (PLPD) subtype has a preferable prognosis, whereas the large cell lymphoma (LCL) subtype involves aggressive disease progression. Reported herein is a case of senile EBV‐BLPD with indolent clinical features and PLPD subtype in the initial phase that recurred as an aggressive lymphoma 3 years after the initial diagnosis. In the recurrent phase, Southern blotting confirmed monoclonal proliferation of large lymphoid B‐cells. In both the initial and recurrent phases, polymerase chain reaction (PCR) yielded a single discrete band of a similar size due to an immunoglobulin heavy‐chain gene rearrangement, indicating that the large lymphoid B‐cells retained identical monoclonality throughout the histological progression and over the whole clinical course. These results suggest that the PLPD subtype is a histological finding in early phase senile EBV‐BLPD and that the LCL subtype reflects the progressive phase of the disease.