What Does 'hyperechoic Focus Along Superior Margin Of Left Kidney Being 1.8*1.3 Cm' Mean?

I have had diarrhea for 3 weeks. My doctor has done blood work, CT scans and an ultrasound of the abdomen. He now has me on an antibiotic for a bacterial infection. The ultrasound report referenced "A hyperechoic focus along the superior margin of the left kidney is approximately 1.8 x 1.8 x1.3 cm in size." My sister has kidney cancer. Should I be concerned.