Histopathologic findings of TAFRO syndrome with immunohistochemical analysis of the kidney specimen: A case report

摘要

TAFRO (Thrombocytopenia, Anasarca, Fever and/or elevated C-reactive protein, Renal dysfunction or Reticulin fibrosis, and Organomegaly) syndrome is a unique systemic inflammatory disease, which has recently been proposed from Japan. We report a case showing TAFRO symptoms, the patient’s condition of which allowed histopathological examinations of several biopsy tissues including the kidney.A 37-year-old man was admitted to our hospital for evaluation of fever of unknown origin, pleural effusion and ascites, renal dysfunction, and lymphadenopathy. Serum IL-6 and VEGF were elevated. Histopathologic findings of the lymph node resembled those of mixed type Castleman disease. The bone marrow biopsy specimen revealed normocellular marrow with a mildly increased number of megakaryocytes, but without obvious fibrosis. The renal biopsy material showed glomerular microangiopathy with double contour of the capillary loops and mesangiolysis. In immunohistochemistry, VEGF was retained in podocytes, whereas IL-6 expression was not limited to the specific sites. Glomerular microangiopathy is regarded as a crucial change in TAFRO syndrome, which should be studied further with regard to VEGF and IL-6.