Differential diagnostics of an abscess at Bioplasm 9d nls is carried out with cysts and with rostate gland cancer sites. Simple cysts and cystic degeneration of prostate gland are sonographically similar to developed prostate abscess, but differ in location (more often: a single central location at congenital cysts or location in the central part against the background of adenomatously changed parenchyma). It is difficult to differentiate an abscess and cancer of prostate gland. Distinctive criteria at Bioplasm 9d nls are considered to be: location – an abscess is more often located in a transitive zone of a gland, but cancer – in peripheral; size – more often an abscess is larger than a tumor, at an abscess – presence of changes in structure and size at dynamic treatment. In diagnostically difficult cases SEA of prostate gland is recommended. In our opinion, location and size are not the exact diagnostic criteria: in the presence of large tumors a cystic component may be present in their structure, which is a site of disintegration. In 8 patients of our research, abscess formation sites were located in a peripheral zone, and the average size of them was small – comparable with a tumor site.