Leukemia cutis. A histopathologic study of 42 cases

Biopsy specimens of skin from 42 patients with leukemia cutis were studied. Typing of leukemia was based on histopathologic and histochemical findings in peripheral blood and bone marrow. There were three patients with acute lymphocytic leukemia, 16 with chronic lymphocytic leukemia, 12 with acute granulocytic leukemia, three with chronic granulocytic leukemia, five with acute monocytic leukemia, and three with acute myelomonocytic leukemia. In general, leukemia cutis shows a diffuse infiltration of leukemic cells in the dermis and subcutaneous tissue, often infiltrating between collagen bundles. Extensive involvement and disruption of blood vessels and skin adnexa are characteristic findings in granulocytic, monocytic, and myelomonocytic leukemia cutis, but biopsy specimens of skin in patients with different types of leukemia show a wide range of histopathologic changes that are variable among the various types of leukemia and sometimes even among different patients with the same type of leukemia. A final typing of leukemia should not rely only on regular histopathologic findings of a skin biopsy, but should depend more on morphologic and histochemical studies of smears of peripheral blood or of bone marrow or both.