Kikuchi-Fujimoto disease: A comprehensive review

Kikuchi-Fujimoto disease, a rare form of necrotizing lymphadenitis, is an uncommon, benign, self-limiting disorder of obscure etiology. It affects mostly young adults of both genders. Clinically, it presents with fever and lymphadenopathy of a firm to rubbery consistency frequently involving cervical lymph nodes while weight loss, splenomegaly, leucopenia, and elevated erythrocyte sedimentation rate feature in severely affected patients. Cutaneous involvement occurs in about 30%-40% of cases as facial erythema and nonspecific erythematous papules, plaques, acneiform or morbilliform lesions of great histologic heterogeneity. Both Kikuchi-Fujimoto disease and systemic lupus erythematosus share an obscure and complex relationship as systemic lupus erythematosus may occasionally precede, develop subsequently, or sometimes be associated concurrently with Kikuchi-Fujimoto disease. It is often mistaken for non-Hodgkin lymphoma while lupus lymphadenitis, cat-scratch disease, Sweet's syndrome, Still's disease, drug eruptions, infectious mononucleosis, and viral or tubercular lymphadenitis are other common differentials. Fine needle aspiration cytology mostly has features of nonspecific reactive lymphadenitis and immunohistochemistry studies usually show variable features of uncertain diagnostic value. Since its diagnosis is exclusively from histopathology, it needs to be evaluated more carefully; an early lymph node biopsy will obviate the need for unnecessary investigations and therapeutic trials. Its treatment with systemic corticosteroids, hydroxychloroquine, or antimicrobial agents mostly remains empirical. The article reviews clinicoepidemiological, diagnostic, and management aspects of KFD from the perspective of practicing clinicians.

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.