Using flow cytometry, we examined the DNA content of six angiomatoid "malignant" fibrous histiocytomas (AMFH), seven nonangiomatoid MFH, and seven myxoid variants of MFH. All six AMFHs were diploid. All nonangiomatoid MFHs and six of seven of the myxoid variant were aneuploid. The clinical course, histological appearance, and ploidy pattern of AMFH are distinctly different from other MFH variants. These differences strongly suggest that AMFH is at the benign end of the clinicobiologic spectrum manifested by "malignant" fibrous histiocytomas.