CD5 and mantle cell lymphoma: Observing the prostate of 1 case of MCL found that secondary small lymphocytes had a blurred nodular distribution, single cell morphology, irregular nucleus, nucleolus was not obvious, mitosis was visible, cytoplasm was scarce, and more transparent degeneration of small blood vessels was visible, and the IHC showed B cell markers CD20, CD79a, CD5, and CyclinD1 diffuse (+) (Figs. 2, 3).