Methotrexate-associated lymphoproliferative disorder with histopathological features of histiocytic necrotizing lymphadenitis.

An 84-year-old Japanese woman suffering from rheumatoid arthritis (RA), who had been treated with methotrexate (MTX) for 15 years, was admitted to our hospital for generalised lymphadenopathy, thrombocytopenia, anaemia, elevated aminotransferases, and elevated CRP levels. Pathological findings of cervical lymph node biopsy were compatible with histiocytic necrotising lymphadenitis (HNL). Small lymphocytes positive for Epstein-Barr virus (EBV)-encoded small RNA were detected in the tissue. We suspected a MTX-associated lymphoproliferative disorder (MTX-LPD), withdrew MTX and administered leucovorin (folic acid). The patient's symptoms gradually resolved following discontinuation of MTX. We considered that this patient developed HNL as an MTX-LPD when EBV was reactivated. This is the first case of HNL associated with MTX treatment for RA, which we report here along with clinical course.

Kikuchi-Fujimoto disease presenting after consumption of 'Miracle Mineral Solution' (sodium chlorite).

We present a case report of a 41-year-old woman of Malay ethnicity who presented with an 11-day history of fever and left-sided lymphadenopathy after consuming 'Miracle Mineral Solution' (sodium chlorite solution) for the first time. A diagnosis of Kikuchi-Fujimoto disease was established via lymph node biopsy after other differentials were excluded. The aetiology of Kikuchi-Fujimoto disease remains controversial, but viral, autoimmune and physicochemical causes have been suggested as possibilities. In this case, we hypothesise that oxidative injury from sodium chlorite initiated an inflammatory response, which triggered the onset of Kikuchi-Fujimoto disease.