1st ultrasound showed an oval-shaped unencapsulated isoechoic mass 2.6 x1.9 x 0.5 cm within subcutaneous fat on my left thigh. 2nd ultrasound, 2 weeks later showed a lipoma measuring 4.5 x 1.5 x 2.1 cm with margins that aren't well demarcated. No increased vascularity identified in either ultrasounds. Could one of the measurements be off? I've had a bump on that thigh for 7 yrs even though 3 yrs. ago ultrasound showed no lipoma. Should I be concerned?