Ghon's complex is a

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by injury or diseases. The term ''Lesion'' is derived from the Latin meaning "injury". Lesions may occur in both plants and animals. Types There is no de ...

seen in the

lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...

that is caused by

tuberculosis Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...

. The lesions consist of a

Ghon focus A Ghon focus is a primary lesion usually subpleural, often in the mid to lower zones, caused by ''mycobacterium tuberculosis, Mycobacterium'' bacilli (tuberculosis) developed in the lung of a nonimmune host (usually a child). It is named for Anto ...

along with pulmonary

lymphadenopathy Lymphadenopathy or adenopathy is a disease of the lymph nodes, in which they are abnormal in size or consistency. Lymphadenopathy of an inflammatory type (the most common type) is lymphadenitis, producing swollen or enlarged lymph nodes. In c ...

within a nearby pulmonary

lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...

. A Ghon's complex retains viable

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

, making them sources of long-term

infection An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmis ...

, which may reactivate and trigger secondary tuberculosis later in life. In countries where cow

milk Milk is a white liquid food produced by the mammary glands of lactating mammals. It is the primary source of nutrition for young mammals (including breastfeeding, breastfed human infants) before they are able to digestion, digest solid food. ...

infected with ''

Mycobacterium bovis ''Mycobacterium bovis'' is a slow-growing (16- to 20-hour generation time) Aerobic organism, aerobic bacterium and the causative agent of tuberculosis in cattle (known as bovine TB). It is related to ''Mycobacterium tuberculosis'', the bacterium ...

'' has been eliminated (due to culling of infected cows and

pasteurization In food processing, pasteurization (American and British English spelling differences#-ise, -ize (-isation, -ization), also pasteurisation) is a process of food preservation in which packaged foods (e.g., milk and fruit juices) are treated wi ...

), primary tuberculosis is usually caused by ''

Mycobacterium tuberculosis ''Mycobacterium tuberculosis'' (M. tb), also known as Koch's bacillus, is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' ha ...

'' and almost always begins in the lungs. Typically, the inhaled

bacilli Bacilli is a Taxonomy (biology), taxonomic Class (biology), class of bacteria that includes two orders, Bacillales and Lactobacillales, which contain several well-known pathogens such as ''Bacillus anthracis'' (the cause of anthrax). ''Bacilli'' ...

implant in the distal airspaces of the lower part of the upper lobe or the upper part of the lower lobe, usually close to the

pleura The pleurae (: pleura) are the two flattened closed sacs filled with pleural fluid, each ensheathing each lung and lining their surrounding tissues, locally appearing as two opposing layers of serous membrane separating the lungs from the med ...

. As sensitization develops, a 1 to 1.5 cm area of gray-white

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

with consolidation emerges, known as the

. In most cases, the center of this focus undergoes caseous necrosis.

Tubercle In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projectio ...

bacilli, either free or within

phagocyte Phagocytes are cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells. Their name comes from the Greek ', "to eat" or "devour", and "-cyte", the suffix in biology denoting "cell", from the Greek ...

s, drain to the regional nodes, which also often caseate. This combination of parenchymal lung lesion and nodal involvement is referred to as the Ghon complex. During the first few weeks, there is also lymphatic and hematogenous dissemination to other parts of the body. In approximately 95% of cases, development of cell-mediated immunity controls the infection.

Differentiation

The Ghon complex undergoes progressive

fibrosis Fibrosis, also known as fibrotic scarring, is the development of fibrous connective tissue in response to an injury. Fibrosis can be a normal connective tissue deposition or excessive tissue deposition caused by a disease. Repeated injuries, ch ...

, often followed by radiologically detectable

calcification Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature M ...

(Ranke complex), and despite seeding of other organs, no lesions develop. Although they are often confused, Ranke complex and Ghon complex are not synonymous. The Ranke complex is an evolution of the Ghon complex (resulting from further healing and calcification of the lesion). The Ghon complex is named after Austrian pathologist

Anton Ghon Anton Ghon (1 January 1866 – 23 April 1936) was an Austrian pathologist and bacteriologist. He is best known for his research on tuberculosis ( Ghon's complex). Biography Ghon was born on January 1, 1866, in Villach. From 1884 to 1890, Gho ...

; the Ranke complex is named in honour of German pulmonologist Karl Ernst Ranke.Ghon's primary lesion
at

Who Named It ''Whonamedit?'' is an online English-language dictionary of medical eponyms and the people associated with their identification. Though it is a dictionary, many eponyms and persons are presented in extensive articles with comprehensive bibliograp ...

References

{{Gram-positive actinobacteria diseases Gross pathology Lung disorders Tuberculosis