Idiopathic multicentric Castleman disease (iMCD) is a polyclonal lymphoproliferative disorder characterized by constitutional symptoms, generalized lymphadenopathy, cytopenias, and multi-organ dysfunction due to excessive cytokines, notably Interleukin-6. Idiopathic multicentric Castleman disease is often sub-classified into iMCD-TAFRO, which is associated with thrombocytopenia (T), anasarca (A), fever/elevated C-reactive protein (F), renal dysfunction (R), and organomegaly (O), and iMCD not otherwise specified (iMCD-NOS), which is typically associated with thrombocytosis and hypergammaglobulinemia. The diagnosis of iMCD is challenging as consensus clinico-pathological diagnostic criteria were only recently established and include several non-specific lymph node histopathological features. Identification of further clinico-pathological features commonly found in iMCD could contribute to more accurate and timely diagnoses. We set out to characterize bone marrow (BM) histopathological features in iMCD, assess differences between iMCD-TAFRO and iMCD-NOS, and determine if these findings are specific to iMCD. Examination of BM specimens from 24 iMCD patients revealed a high proportion with hypercellularity, megakaryocytic atypia, reticulin fibrosis, and plasmacytosis across patients with both iMCD-NOS and iMCD-TAFRO with significantly more megakaryocytic hyperplasia (p = 0.001) in the iMCD-TAFRO cases. These findings were also consistent with BM findings from 185 published cases of iMCD-NOS and iMCD-TAFRO. However, these findings are relatively nonspecific as they can be seen in various other infectious, malignant, and autoimmune diseases.

TAFRO syndrome is a newly proposed disease that is characterised by thrombocytopenia, anasarca, fever, reticulin fibrosis (or renal dysfunction), and organomegaly. Generally, high doses of corticosteroids are recommended for the initial treatment of TAFRO syndrome; however, some patients experience prolonged refractory thrombocytopenia after initiating such therapies. If corticosteroid treatment alone is ineffective, additional immunosuppressive therapies such as cyclosporine A are recommended. Since long-term use of immunosuppressive therapies with TAFRO syndrome sometimes causes serious infection, it is important to recognise the time to recovery from thrombocytopenia. In this study, we investigated how long it took to recover from thrombocytopenia, to aid clinicians in decision-making regarding the need to strengthen treatment for prolonged thrombocytopenia. Here, we describe three of our patients with TAFRO syndrome exhibiting prolonged thrombocytopenia. We also investigated the median period to recovery from this complication (defined as the time to increase the platelet count above 50,000/µL) after the initiation of high-dose corticosteroid treatment in our 3 cases and 38 peer-reviewed cases. We found that it took our patients 61 days to recover from thrombocytopenia; in comparison, our investigation of the 38 peer-reviewed case reports revealed a median recovery time of 47.5 days among previously reported patients. We showed the time to recovery from thrombocytopenia in patients with TAFRO syndrome for the first time. Our findings ought to be useful for decision-making among clinicians regarding the administration of other immunosuppressive treatments in addition to corticosteroid.

TAFRO is an acrostic and includes thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis (R) and organomegaly (O) (Takai et al., 2013). TAFRO syndrome has been described firstly by Takai in Japanese patients. However TAFRO cases have been reported from US, Europe and other countries (Takai et al., 2010; Iwaki et al., 2016; Abdo et al., 2014). Three major and at least one minor criteria and exclusion of infectious, rheumatologic and neoplastic diseases are required for the diagnosis of TAFRO. In fact TAFRO must be thought in clinically undiagnosed and unsolved problemmatic cases.

Thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly (TAFRO) syndrome is considered as a unique clinicopathologic variant of multicentric Castleman\'s disease and is recently reported in Japan. This entity represents a severe inflammatory state leading to organ failures such as severe liver dysfunction seen in our case, and can be treated by immunosuppressive agents, steroids, and cyclosporine shown in several case reports. A systematic review and our case suggest the potential utility of tocilizumab as a treatment for TAFRO syndrome.

Recently, more than ten cases of thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly (TAFRO) syndrome or Castleman-Kojima disease exhibiting such symptoms as thrombocytopenia, anasarca, fever, reticulin fibrosis and organomegaly have been reported in Japan. We have found two cases of TAFRO syndrome and have reviewed another eighteen previously reported cases. Histological findings of the lymph nodes and levels of interleukin 6 (IL-6) and vascular endothelial growth factor in both serum/plasma and effusions are important characteristics for diagnosing this syndrome.