A Case of Thrombocytopenia, Anasarca (Edema, Pleural Effusion, and Ascites), Fever, Reticulin Fibrosis/Renal Dysfunction, and Organomegaly (TAFRO) Syndrome Initially Not Presenting With Thrombocytopenia: A Role of Immature Platelet Fraction.

Thrombocytopenia, anasarca (edema, pleural effusion, and ascites), fever, reticulin fibrosis/renal dysfunction, and organomegaly (TAFRO) syndrome is a rare and severe systemic disease. The emergence of thrombocytopenia, however, may be preceded by other signs or symptoms, which could delay the diagnosis of the disease. We reported a case in which an increased immature platelet fraction (IPF), a surrogate marker for megakaryocytic activity, preceded the development of thrombocytopenia, and finally, we diagnosed the patient with TAFRO syndrome. A 79-year-old male with a previous history of uninephrectomy due to bladder and ureteral cancer was admitted to our hospital because of massive edema and progressive impairment in renal function. On admission, inguinal lymphadenopathy, elevated C-reactive protein (CRP), bilateral pleural effusion, and ascites were observed, and the lymph node biopsy showed that atrophic lymphoid follicles and germinal centers were observed along with prominent glomeruloid vascular proliferation and the expansion of the interfollicular spaces consistent with the feature of Castleman's disease. The peripheral platelet count did not reach the level of the criteria for TAFRO syndrome (13.9×10/µL), but the immature platelet fraction was increased (11.6%), and bone marrow biopsy revealed hyperplasia of megakaryocytes. During the course of the preemptive treatment with prednisolone and tocilizumab, thrombocytopenia was uncovered, and the patient was finally diagnosed as having TAFRO syndrome. Thus, the present case may offer valuable information on the role of the immature platelet fraction in the establishment of the early diagnosis of TAFRO syndrome.