Sentence:  <WSD>Microscopically</WSD> , both kidneys showed many small cortical scars in which there was glomerular and interstitial fibrosis , tubular atrophy , and an infiltration of lymphocytes and plasma cells . 
Meaning of the word marked with <WSD> tags:  by using a microscope; so as to be visible only with a microscope; as seen with a microscope