Two cases of soft-tissue atypical lipomatous tumors with areas of smooth mu
scle cell differentiation are presented. The patients were a 72-year-old ma
n (Case 1) and a 62-year-old woman (Case 2); their neoplasms were located i
n the left inguinal region and on the chest, respectively. The adipocytic c
omponent in Case 1 contained cells with nuclear atypism and lipoblasts. Cas
e 2 showed only slight nuclear atypism and lacked any lipoblasts. Smooth mu
scle fascicles were composed of well-differentiated cells with a few mitose
s having none or only a slight atypism. They expressed muscle-specific acti
n and desmin in both cases. No recurrence was recorded during the follow-up
time.