World Health Organization-European Organization for Research and Treatment of Cancer classification of cutaneous lymphoma in Korea: A retrospective study at a single tertiary institution

Background: The relative frequency and the clinicopathological characteristics of lymphoma may vary according to geography and ethnicity. Data are limited regarding the features of cutaneous lymphoma (CL) presented according to the World Health Organization (WHO) and the European Organization for Research and Treatment of Cancer (EORTC) classification (2005) in Korea. Objective: The study determined the relative frequency of CL in Korea and presented the clinical relevance of CL based on the WHO-EORTC classification. Methods: We reclassified the cases of CL collected over a 16-year period in a tertiary institution-based dermatologic setting in Korea. Results: In all, 164 cases were divided into 96 primary and 68 secondary CL. The group of primary CL consisted of T- and natural killer-cell lymphomas (84.3%), B-cell lymphomas (13.5%), and immature hematopoietic malignancies (2%). The Korean population presented with a higher rate of T-cell and natural killer-/T-cell CL and a lower rate of cutaneous B-cell lymphoma than Western countries. Compared with 2003 Korean data, the rate of mycosis fungoides was lower and the rate of nasal and nasal-type natural killer-/T-cell lymphomas was higher. Limitations: This study was retrospective and based on a single-center experience. Conclusion: As the relative frequency of lymphomas differs widely with geography and ethnicity, there is a need to collect more data to describe the epidemiologic characteristics in the Far East.