Michaelis-Gutmann bodies (M-G bodies) are concentrically layered basophilic inclusions found in the urinary tract. They are 2 to 10 μm in diameter, and are thought to represent remnants of phagosome

Phagosome

In cell biology, a phagosome is a vacuole formed around a particle absorbed by phagocytosis. The vacuole is formed by the fusion of the cell membrane around the particle. A phagosome is a cellular compartment in which pathogenic microorganisms can be killed and digested...

s mineralized by iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 and calcium

Calcium

Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

 deposits.

M-G bodies are a pathognomonic

Pathognomonic

Pathognomonic is a term, often used in medicine, that means characteristic for a particular disease. A pathognomonic sign is a particular sign whose presence means that a particular disease is present beyond any doubt...

 feature of malakoplakia

Malakoplakia

Malakoplakia is a rare inflammatory condition which makes its presence known as a papule, plaque or ulceration that usually affects the genitourinary tract. However, it may also be associated with other bodily organs. It was initially described in the early 1900s as soft yellowish plaques found on...

, an inflammatory condition that affects the genitourinary tract. They were discovered in 1902 by Leonor Michaelis

Leonor Michaelis

Leonor Michaelis was a German biochemist, physical chemist, and physician, known primarily for his work with Maud Menten on enzyme kinetics and Michaelis-Menten kinetics in 1913.-Early life and education:...

and Carl Gutmann.