[Complete response by rituximab monotherapy in a patient with leukemic mantle cell lymphoma diagnosed by fluorescence in situ hybridization analysis].

An 85-year-old male was admitted to a hospital with abdominal discomfort in October, 2010. Severe splenomegaly and mild para-aortic lymphoadenopathy were detected. In addition, an increase in atypical lymphocytes was noticed by bone marrow analyses with weak positive staining of cyclin D1. Subsequently, the fluorescence in situ hybridization(FISH)method confirmed cyclin D1 reconstruction, and the fusion signals of the BCL1 and IgH genes were detected, thus providing a definitive diagnosis of leukemic mantle cell lymphoma. After treatment with rituximab monotherapy, the Ki-67 index was stabilized to within 10%, and complete response was obtained.