Chest x-ray of Ghon's complex of active tuberculosis

Ghon's complex is a

lesion A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals. Types There is no designated classif ...

seen in the lung that is caused by

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in w ...

. The lesions consist of a Ghon focus along with pulmonary lymphadenopathy within a nearby pulmonary lymph node. A Ghons complex retains viable

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

, making them sources of long-term

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable d ...

, 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 mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modulati ...

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

pasteurization Pasteurization or pasteurisation is a process of food preservation in which packaged and non-packaged foods (such as milk and fruit juices) are treated with mild heat, usually to less than , to eliminate pathogens and extend shelf life. T ...

), primary tuberculosis is usually caused by '' Mycobacterium tuberculosis'' and almost always begins in the lungs. Typically, the inhaled 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. As sensitization develops, a 1 to 1.5 cm area of gray-white

inflammation Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...

with consolidation emerges, known as the Ghon focus. In most cases, the center of this focus undergoes caseous necrosis. Tubercle bacilli, either free or within phagocytes, drain to the

regional node In geography, regions, otherwise referred to as zones, lands or territories, are areas that are broadly divided by physical characteristics (physical geography), human impact characteristics (human geography), and the interaction of humanity and t ...

s, which also often caseate. This combination of

parenchymal lung lesion Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word π ...

and

nodal involvement Nodal homolog is a secretory protein that in humans is encoded by the ''NODAL'' gene which is located on chromosome 10q22.1. It belongs to the transforming growth factor beta superfamily (TGF-β superfamily). Like many other members of this superf ...

is referred to as the Ghon complex. During the first few weeks, there is also lymphatic and

hematogenous dissemination Bloodstream infections (BSIs), which include bacteremias when the infections are bacterial and fungemias when the infections are fungal, are infections present in the blood. Blood is normally a sterile environment, so the detection of micro ...

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, 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, Ghon ...

; the Ranke complex is named in honour of German pulmonologist

Karl Ernst Ranke Karl Ernst Ranke (29 January 1870 in Munich – 9 November 1926 in Munich) was a German internist, pediatrician and pulmonologist known for his research of tuberculosis. He was the son of anthropologist Johannes Ranke (1836–1916). In 1896 h ...

.Ghon's primary lesion
at Who Named It

References

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