Three cases of spindle cell lipoma, myxoid variant

Here we report 3 cases of spindle cell lipoma (SCL) that developed in relatively rare physical regions. Case1 : A 57-yearold woman had a 2 cm subcutaneous mass in her right buttock. A T1 weighted MRI image showed high and low mixing areas. The T1 low area was intensivelyenhanced, and the T1 high area was suppressed bya T2 weighted gadoliniumenhanced fat-suppressed image. The resected tumor was whitish yellow with glutinous secretion on the surface. Case2 : A 67-year-old man had a 9 × 8 × 5 cm pedunculated mass on his left lower leg. MRI showed somewhat similar findings to those of Case1. The split surface of the resected tumor was yellow, and the tumor had a jelly-like texture. Case3 : An 81-year-old man had a 2.5 cm dome-shaped elevated subcutaneous mass in the center of his forehead. An ultrasonic examination showed a mass that had an intensityequal to that of the surrounding adipose tissue. The resected tumor was yellow and contained a mucus-like viscous liquid. Pathological examinations revealed that these tumors were composed of a mixture of fat tissue, spindle cells, and collagen fibers with a mucinous matrix. Spindle-shaped tumor cells were positive for CD34, and the mucinous matrix was positive for Alcian-blue. SCL, myxoid variant were diagnosed in all of the 3 cases based on these findings. It seems that SCL should be suspected in spite of the location of the subcutaneous tumor, if the tumor shows atypical radiologic findings. Histologically, SCL is characterized by proliferation of mature adipocytes, collagen fibers, and spindle cells showing stronglypositive reaction for CD34. Moreover, the findings of the Alcian-blue positive mucin, spreading through the tumor, would enable the definitive diagnosis of the mixoid variant of SCL.