Hairy Cell leukaemia

Clinical Features

§   Splenomegaly and pancytopenia, esp. monocytopenia

§   Recuurent opportunistic infections

§   Vasculitis or immune dysfunction

Morphology

§        Oval or indented nucleus

§        Nucleoli are typically absent

§        Abundant cytoplasm with hairy projections

§        TRAP positivity

§        Aspirate frequently dry tap

§        Trephine

§        Fried egg appearance

§        Increased reticulin

§        Spleen

§        Infiltrate localises to red pulp

§        White pulp is atrophic

§        Red blood cell lakes lined by hairy cells

Immunophenotype

§   SIg, B cell marker positive

§   Negative : CD5, CD10, CD23

§   Positive : CD11c, CD20, CD25, CD103, CD123, FMC7

§   HCLv : CD25, CD103 negative, CD23 positive

Treatment

§        Caldrabine and Pentostatin

§        CR in 80-85%

§        May be combined with rituximab

§        (splenectomy and interferon)

Hairy cell variant

§   Bone marrow and spleen histology resemble HCL

§   HCLs – prominent nucleolus with villous cytoplasm

§   Present with a high wcc

§   Monocytopenia absent

§   TRAP negative

§   Poor response to HCL treatment and hence worse prognosis