Skin manifestations in CD4+, CD56+ malignancies.

CD4+ CD56+ hematologic neoplasms were recently individualized. We report three cases of CD4+ CD56+ malignancies with cutaneous lesions in three cases and also bone marrow involvement in two cases. Two patients relapsed 2 and 3 months after polychemotherapy. Two patients died within 3-10 months. A constant immunophenotype was observed with the co-expression of CD4 and CD56, the absence of B and T-cell markers. The salient fact of this report is the presence of T-cell clonal rearrangement. The clinical and pathological features closely resemble the specific cutaneous manifestations in acute leukemia with monocytic differentiation, especially the granulocytic sarcoma. Because of the positivity of the CD56, natural killer cell proliferations were discussed. Since 1994, 50 cases of CD4+, CD56+ cutaneous neoplasms have been reported with specific clinical, cytologic and immunohistochemical features. The diagnosis is more difficult when the cutaneous location is exclusive; on the contrary, the cytological features of the blood and medullar cells with cytoplasmic vacuoles and pseudopodia are characteristic of this hematologic neoplasm. The presence of CD123 antigen in most of the cases is an argument for a plasmacytoid dendritic cell proliferation and it is also a good marker for primary cutaneous lesions.