1. 1) Tokuhira M, Tamaru J, Kizaki M. Clinical management for other iatrogenic immunodeficiency-associated lymphoprolifer ative disorders. J Clin Exp Hematop 2019; 59: 72–92.
2. 2) Ellman MH, Hurwitz H, Thomas C, et al. Lymphoma developing in a patient with rheumatoid arthritis taking low dose weekly methotrexate. J Rheumatol 1991; 18: 1741–1743.
3. 3) Gaulard P, Swerdlow SH, Harris NL, et al. Other iatrogenic immunodeficiency associated lymphoproliferative disorders. In: Swerdlow SH, Campo E, Harris NL, et al, editor: WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues. Revised 4th ed. Lyon, IARC, 2017; 462–464.
4. 4) Hoshida Y, Xu JX, Fujita S, et al. Lymphoproliferative disorders in rheumatoid arthritis: clinicopathological analysis of 76 cases in relation to methotrexate medication. J Rheumatol 2007; 34: 322–331.
5. 5) Salloum E, Cooper DL, Howe G, et al. Spontaneous regression of lymphoproliferative disorders in patients treated with methotrexate for rheumatoid arthritis and other rheumatic diseases. J Clin Oncol 1996; 14: 1943–1949.