[Four cases of CD7-positive acute myeloid leukemia]

This report describes 4 cases of T-cell-associated CD7-positive acute myeloid leukemia (AML). Myelo-peroxidase staining of blasts was negative in 2 cases but became positive during their courses. In all cases, the myeloid determinants CD13 and/or CD33 were associated with CD7 expression. Other B-lymphoid (CD10, CD19) or T-lymphoid (CD2) markers were negative. In three cases, dual fluorescence analyses showed co-expression of CD7 and CD13 (CD33). Clinically, compared with CD7+AML, these CD7+AML patients presented higher leukocyte and blast counts in peripheral blood. All patients achieved complete remission with chemotherapeutic regimens for AML, but 3 relapsed within a short time. Systemic lymphadenopathy was found in 2 cases, and interestingly, the surface markers of the lymph-node in one case were CD7+CD33-. These cases of CD7+AML may represent a distinct subgroup that arises from particular, less different myeloid precursors, and may have poor prognosis.