What medical term describes solid masses caused from filtrate in the renal system?

The term that accurately describes solid masses formed from filtrate in the renal system is "renal calculi." Renal calculi, commonly known as kidney stones, are hard deposits made of minerals and salts that form in the kidneys when the urine becomes concentrated. This concentration of minerals leads to precipitation and the subsequent formation of solid masses, which can vary in size.

Understanding the formation of renal calculi involves recognizing how certain conditions, such as dehydration or urinary tract infection, can alter the normal balance of substances in the urine, prompting the development of stones. The presence of renal calculi is clinically significant as they can obstruct urine flow, cause pain, and lead to complications like infection or kidney damage.

In contrast, nephrotoxins refer to substances that can damage kidney cells, cysts are fluid-filled sacs that can develop in various tissues including the kidneys but are not solid masses formed from filtrate, and hydronephrosis refers to the swelling of a kidney due to a build-up of urine, which is a consequence of blockage and not a solid mass itself.