Wright stain of hairy Cells:
L-26 in Marrow:
Hairy cell leukemia is a rare, low-grade neoplasm of mature B-cells affecting predominantly older adult males. Blood, marrow, and spleen are involved. Patients usually present with an enlarged spleen and pancytopenia with notable absolute neutropenia and monocytopenia. Typically, only a few circulating hairy cells are found. As shown in the image, they are medium-sized with an oval or "peanut-shaped" nucleus, and a moderate amount of cytoplasm which has a fringed edge (hairy projections). The infiltrate is subtle in the marrow; staining with L-26 (for CD20) brings out the hairy cells, shown in brown on the second image. Hairy cells also show "tartrate resistant reactivity for acid phosphatase," whereas other cells lose their reactivity. The "TRAP" reactivity is shown by the bright red staining in the third image.
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