Cell of origin of hairy cell leukemia is -: (A) B-cell, (B) T-cell, (C) NK-cell, (D) Dendritic reticulum cell
Answer is A. Hairy cell leukaemia is an unusual & uncommon form of B cell malignancy characterized by presence of hairy cells in the blood & bone marrow & splenomegaly.Hairy cells are abnormal mononuclear cells with hairy cytoplasmic projections which are seen in blood,bone marrow & spleen.These cells exhibit CD19,CD20 & CD22 antigen.Reference: Harsh mohan textbook of pathology 6 th edition pg no 379