Caseous necrosis or caseous degeneration () is a unique form of cell death in which the tissue maintains a cheese-like appearance.Robbins and Cotran: Pathologic Basis of Disease, 8th Ed. 2010. Pg. 16 Unlike with

coagulative necrosis Coagulative necrosis is a type of accidental cell death typically caused by ischemia or infarction. In coagulative necrosis, the architectures of dead tissue are preserved for at least a couple of days. It is believed that the injury denatures stru ...

, tissue structure is destroyed. Caseous necrosis is enclosed within a

granuloma A granuloma is an aggregation of macrophages (along with other cells) that forms in response to chronic inflammation. This occurs when the immune system attempts to isolate foreign substances that it is otherwise unable to eliminate. Such sub ...

. Caseous necrosis is most notably associated with tuberculoma. The dead tissue appears as a soft and white proteinaceous dead cell mass. The term ''caseous'' means 'pertaining or related to

cheese Cheese is a type of dairy product produced in a range of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk (usually the milk of cows, buffalo, goats or sheep). During prod ...

', and comes from the Latin word 'cheese'.

Histology

In caseous necrosis no histological architecture is preserved (unlike with

). On microscopic examination with H&E staining, the area is acellular, characterised by amorphous, roughly granular eosinophilic debris of now dead cells, also containing interspearsed haematoxyphilic remnants of cell nucleus contents. This caseus necrotic center is enclosed within a

Causes

Frequently caseous necrosis is characteristically associated with tuberculomas. A similar appearance can be associated with

histoplasmosis Histoplasmosis is a fungal infection caused by ''Histoplasma capsulatum''. Symptoms of this infection vary greatly, but the disease affects primarily the lungs. Occasionally, other organs are affected; called disseminated histoplasmosis, it can ...

cryptococcosis Cryptococcosis is a potentially fatal fungal infection of mainly the lungs, presenting as a pneumonia, and in the brain, where it appears as a meningitis. Coughing, difficulty breathing, chest pain and fever are seen when the lungs are infect ...

, and

coccidioidomycosis Coccidioidomycosis (, ) is a mammalian mycosis, fungal disease caused by ''Coccidioides immitis'' or ''Coccidioides posadasii''. It is commonly known as cocci, Valley fever, California fever, desert rheumatism, or San Joaquin Valley fever. Cocci ...

Pathophysiology

This begins as infection is recognized by the body and

macrophage Macrophages (; abbreviated MPhi, φ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that ...

s begin walling off the

microorganism A microorganism, or microbe, is an organism of microscopic scale, microscopic size, which may exist in its unicellular organism, single-celled form or as a Colony (biology)#Microbial colonies, colony of cells. The possible existence of unseen ...

s or

pathogens In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term ...

. As macrophages release chemicals that digest cells, the cells begin to die. As the cells die they disintegrate but are not completely digested and the debris of the disintegrated cells clump together creating soft granular mass that has the appearance of cheese. As cell death begins, the granuloma forms and cell death continues the inflammatory response is mediated by a type IV hypersensitivity reaction. Some data suggests that the epithelioid morphology and associated barrier function of host macrophages associated with

s may prevent effective immune clearance of mycobacteria.

References

External links

Microscope images of caseous necrosis

{{Pathology Histopathology Tuberculosis Necrosis