A focal lung pneumatosis, is an enclosed pocket of air or gas in the lung and includes blebs, bullae, pulmonary cysts, and lung cavities. Blebs and bullae can be classified by their wall thickness. * A bleb has a wall thickness of less than 1 mm. By radiology definition, it is up to 1 cm in total size. By pathology definition, it originates in the

pleurae The pulmonary pleurae (''sing.'' pleura) are the two opposing layers of serous membrane overlying the lungs and the inside of the surrounding chest walls. The inner pleura, called the visceral pleura, covers the surface of each lung and dips be ...

(rather than in the lung parenchyma). *A bulla has a wall thickness of less than 1 mm. By radiology definition, it has a total size of greater than 1 cm. By pathology definition, it originates in the lung parenchyma (rather than in the pleurae). * A lung cyst has a wall thickness of up to 4 mm. A minimum wall thickness of 1 mm has been suggested, but thin-walled pockets may be included in the definition as well. * A cavity has a wall thickness of more than 4 mm. The terms above, when referring to sites other than the lungs, often imply fluid content. Lung cysts are seen in about 8% of the general population, with an increased prevalence in older people, and are not associated with emphysema. They may be part of the aging changes of the lungs, and cause a slight decrease in their

diffusing capacity Diffusing capacity of the lung (DL) (also known as Transfer factor is another expression for the formerly used diffusing capacity.) measures the transfer of gas from air in the lung, to the red blood cells in lung blood vessels. It is part of a c ...

. The presence of multiple pulmonary cysts may indicate a need to evaluate the possibility of bullous or cystic lung diseases. Cavitation indicates workup for serious infection or

lung cancer Lung cancer, also known as lung carcinoma (since about 98–99% of all lung cancers are carcinomas), is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung. Lung carcinomas derive from transformed, malign ...

Bleb or bulla

The most common disease causing blebs or bullae is

paraseptal emphysema Emphysema, or pulmonary emphysema, is a lower respiratory tract disease, characterised by air-filled spaces ( pneumatoses) in the lungs, that can vary in size and may be very large. The spaces are caused by the breakdown of the walls of the alv ...

though

centrilobular emphysema Emphysema, or pulmonary emphysema, is a lower respiratory tract disease, characterised by air-filled spaces ( pneumatoses) in the lungs, that can vary in size and may be very large. The spaces are caused by the breakdown of the walls of the alv ...

may sometimes be involved. Other conditions associated with lung bullae are: *

Alpha 1-antitrypsin deficiency Alpha-1 antitrypsin deficiency (A1AD or AATD) is a genetic disorder that may result in lung disease or liver disease. Onset of lung problems is typically between 20 and 50 years of age. This may result in shortness of breath, wheezing, or an inc ...

Updated: Feb 21, 2019 * Marfan syndrome *

Ehlers–Danlos syndromes Ehlers–Danlos syndromes (EDS) are a group of 13 genetic connective-tissue disorders in the current classification, with the latest type discovered in 2018. Symptoms include loose joints, joint pain, stretchy velvety skin, and abnormal scar fo ...

Cocaine Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South Ameri ...

smoking *

Sarcoidosis Sarcoidosis (also known as ''Besnier-Boeck-Schaumann disease'') is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly a ...

HIV/AIDS Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual ...

* Intravenous substance abuse

Cyst

A pulmonary cyst is not necessarily the same type of cyst seen in many cystic lung diseases. The cyst for example in pneumocystis pneumonia is not the same as the pulmonary cyst. CT of lymphocytic interstitial pneumonia

CT of lymphocytic interstitial pneumonia

Cystic lung diseases include: *

Langerhans cell histiocytosis Langerhans cell histiocytosis (LCH) is an abnormal clonal proliferation of Langerhans cells, abnormal cells deriving from bone marrow and capable of migrating from skin to lymph nodes. Symptoms range from isolated bone lesions to multisystem d ...

(LCH) *

Lymphangioleiomyomatosis Lymphangioleiomyomatosis (LAM) is a rare, progressive and systemic disease that typically results in cystic lung destruction. It predominantly affects women, especially during childbearing years. The term sporadic LAM is used for patients with LAM ...

(LAM) *

Lymphocytic interstitial pneumonia Lymphocytic interstitial pneumonia (LIP) is a syndrome secondary to autoimmune and other lymphoproliferative disorders. Symptoms include fever, cough, and shortness of breath. Lymphocytic interstitial pneumonia applies to disorders associated w ...

(LIP) *

Birt–Hogg–Dubé syndrome Birt–Hogg–Dubé syndrome (BHD), also Hornstein–Birt–Hogg–Dubé syndrome, Hornstein–Knickenberg syndrome, and fibrofolliculomas with trichodiscomas and acrochordons is a human autosomal dominant genetic disorder that can cause suscept ...

* ''Pneumocystis'' pneumonia * Pulmonary amyloidosis *

Light chain deposition disease Light chain deposition disease (LCDD) is a rare blood cell disease which is characterized by deposition of fragments of infection-fighting immunoglobulins, called light chains (LCs), in the body. LCs are normally cleared by the kidneys, but in ...

Lung metastases Lung cancer, also known as lung carcinoma (since about 98–99% of all lung cancers are carcinomas), is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung. Lung carcinomas derive from transformed, malign ...

rarely cause multiple cystic lung lesions. This form of presentation has been described in metastatic

sarcoma A sarcoma is a malignant tumor, a type of cancer that arises from transformed cells of mesenchymal ( connective tissue) origin. Connective tissue is a broad term that includes bone, cartilage, fat, vascular, or hematopoietic tissues, and sar ...

Incidental blebs and cysts

A focal lung pneumatosis that is an

incidental imaging finding In medical or research imaging, an incidental imaging finding (also called an incidentaloma) is an unanticipated finding which is not related to the original diagnostic inquiry. As with other types of incidental medical findings, they may represe ...

such as on a CT scan, without suspicious findings (such as findings indicating any of the diseases listed above), generally does not indicate further follow-up.

Cavity

Two infectious diseases that are commonly associated with cavities of lung tissue are '' Mycobacterium tuberculosis'' and ''

Klebsiella pneumoniae ''Klebsiella pneumoniae'' is a Gram-negative, non-motile, encapsulated, lactose- fermenting, facultative anaerobic, rod-shaped bacterium. It appears as a mucoid lactose fermenter on MacConkey agar. Although found in the normal flora of the mo ...

''. The formation of cavities is due to tissue necrosis and creates an environment that allows the pathogen to expand in numbers and spread further. In the absence of infectious symptoms, a

lung nodule A lung nodule or pulmonary nodule is a relatively small focal density in the lung. A solitary pulmonary nodule (SPN) or coin lesion, is a mass in the lung smaller than three centimeters in diameter. A pulmonary micronodule has a diameter of less ...

with cavitation is a suspected

References

{{reflist Lung disorders