Clinicopathological features of clinical methotrexate-related lymphoproliferative disorders.

Methotrexate (MTX) is one of the potent drugs for autoimmune diseases (ADs), especially for rheumatoid arthritis. Recent studies suggest that MTX should be immediately withdrawn when patients with AD develop lymphoproliferative disorder (LPD). However, biopsy cannot be performed for diagnosis because LPD regresses quickly after MTX withdrawal, thus making clinical MTX-LPD (c-MTX-LPD) challenging to diagnose. In this study, among the 28 patients with c-MTX-LPD, seven developed a proven LPD (p-LPD) after suspicious LPD (s-LPD) regression, six of which were Hodgkin lymphoma. Four of seven patients with p-LPD + died, whereas all patients with p-LPD- survived. The clinical manifestations indicative of p-LPD include fever, elevated serum C-reactive protein level, and soluble interleukin-2 receptor level. Anti-AD drugs did not appear to affect the pathogenesis of p-LPD development. P-LPD was not observed after 3 years from the time of s-LPD regression.