Molecular genetic diagnosis of a primary central nervous system T cell lymphoma

Primary central nervous system T cell lymphomas are rare tumors. Histologically, they may be indistinguishable from other entities like inflammatory processes. In such cases, molecular genetic verification of clonal T cell receptor (TCR) gene rearrangements is an indispensable diagnostic tool. Here we present a case where identification of TCR beta and gamma gene rearrangements by polymerase chain reaction was used to differentiate between a vasculitis and a primary CNS T cell lymphoma, which has profound consequences for therapy management and outcome.