Rising incidence of primary central nervous system lymphoma in Kumamoto, Japan

Background: Primary central nervous system lymphoma is an extranodal form of non-Hodgkin lymphoma arising in the cramospinal axis. The incidence of PCNSL is reportedly on the increase in some parts of the world in the last 2 decades. Methods: We surveyed 4007 patients diagnosed with PIT between 1989 and 2004, with histologic diagnosis being obtained in 70% of the patients. Of these, the PCNSL cases were reviewed. Results: Of 4007, 136 (3.4%) carried a diagnosis of PCNSL. At 0.41 per 100,000 per year, the age-adjusted incidence rate for that period was higher than that for the period from 1989 to 1998 (0.29 per 100,000 per year). Moreover, the number of patients with PCNSL doubled from 45 (1989-1996) to 91 (1997-2004). Conclusions: Our findings point to an increase in the incidence of PCNSL among immunocompetent individuals in Kumamoto Prefecture. (c) 2006 Elsevier Inc. All rights reserved.