RESUMEN
TAFRO syndrome is a rare systemic inflammatory disorder of unknown etiology characterized by thrombocytopenia, anasarca, fever, reticulin myelofibrosis, renal dysfunction, and organomegaly. The diagnosis of TAFRO syndrome can be challenging; however, prompt diagnosis is vital because TAFRO syndrome is a progressive and life-threatening disease. We have showcased five patients with TAFRO syndrome who had similar bone marrow (BM) findings that could be considered the findings that characterize TAFRO syndrome. All patients were treated with corticosteroids and tocilizumab; three of the five patients (60 %) responded positively to the treatment. The unique BM findings observed in this study were megakaryocytes with distinct multinuclei and three-dimensional and indistinct bizarre nuclei ("dysmorphic megakaryocyte"), similar to the megakaryocyte morphology observed in myeloproliferative neoplasms (MPNs). Notably, dysmorphic megakaryocytes were observed in all five cases, whereas only two of the five patients tested positive for reticulin myelofibrosis, and three of the five patients had megakaryocytic hyperplasia, which are considered typical findings of TAFRO syndrome. Thus, the BM findings of dysmorphic megakaryocytes could help in the correct and immediate diagnosis of TAFRO syndrome.