[Atypical hemolytic uremic syndrome in an elderly patient successfully treated with eculizumab].

Herein, we present an elderly onset case of aHUS successfully treated with eculizumab. An 80-year-old woman with severe anemia, thrombocytopenia, and acute renal dysfunction was admitted to our hospital. A laboratory test revealed steep elevation in the LDH level, and the peripheral blood smear showed erythrocyte fragmentations. Accordingly, we diagnosed thrombotic microangiopathy, and treatment with plasma exchange was immediately initiated. In addition, she required hemodialysis because of rapid impairment of the renal function. After excluding Shiga toxin-producing Escherichia coli infection and malignancy and confirming her ADMTS13 activity above 10%, we diagnosed aHUS, according to the Japanese diagnostic criteria for aHUS. Next, we initiated treatment with eculizumab. Her hematological findings improved 23 days after the starting of eculizumab. In addition, her renal function gradually recovered, and hemodialysis was discontinued. The genetic test for several complement regulatory genes tested negative. The onset of aHUS is reported in children or young adults and is rarely reported in elderly. However, our case suggests the importance of precisely diagnosing aHUS and initiating early administration of eculizumab for improving the outcome even in elderly patients.

18F-FDG-PET/CT is effective in distinguishing myelofibrosis due to bone marrow infiltration of diffuse large B-cell lymphoma from triple-negative primary myelofibrosis.

Although myelofibrosis is mainly associated with myeloproliferative neoplasms (MPN), especially primary myelofibrosis (PMF), a variety of hematological malignancies, including acute myeloid leukemia, multiple myeloma and malignant lymphoma, also cause myelofibrosis with markedly varying degrees of severity. Thus, it is extremely important to accurately diagnose the underlying diseases that cause fibrosis in bone marrow. Analyses of JAK2, MPL and calreticulin gene mutations are useful for distinguishing MPN from other diseases, since 90% of MPN patients have a mutation in one of these genes. However, 10% of PMF patients do not have mutations in any of these genes, and these patients have a disease known as triple negative PMF. It is sometimes difficult to accurately distinguish triple negative PMF from secondary myelofibrosis caused by other diseases. Herein, we present a case of diffuse large B cell lymphoma (DLBCL) with bone marrow involvement, mimicking triple negative primary myelofibrosis. 18F-FDG-PET was useful for correctly diagnosing DLBCL.