AMLs are composed of variable amounts of adipose tissue, smooth muscle, and vasculature . More than 90% of tumors contain at least focal areas of mature adipose tissue . Fat cells resembling lipoblasts are rarely seen. The smooth muscle component ranges from fascicles of elongated spindle cells with cigar-shaped nuclei to sheets of epithelioid cells with abundant eosinophilic granular cytoplasm. The smooth muscle cells often appear to originate and radiate from vessel walls. The morphology of the vascular component is variable. Thickened and hyalinized vessels with eccentric lumens are seen in most cases. Antibodies to several melanoma-related antigens, including HMB-45 and A-103 (melan-A/MART-1), are at least focally positive in the majority of cases. In general, from 5% to 10% of cells are immunoreactive with these antibodies . The epithelioid smooth muscle cell components are most consistently positive with these antibodies, although the spindled smooth muscle and adipose tissue components also may be positive. This observation is of particular importance in the subset of AML with a predominance of adipose tissue or spindled smooth muscle. (Sternberg’s 5th ed).