Pulmonary manifestations of yellow nail syndrome are principally centered around
effects for recurrent lung infections (bronchiectasis) and
The role of proposed lymphatic impairment could account for the development of pleural effusions and smooth interlobular...
Pulmonary mycobacterium malmoense infection is a form of pulmonary non-tuberculous mycobacterial infection occurring related to Mycobacterium malmoense. It is among the most frequently isolated and clinically relevant non-tuberculous mycobacteria (NTM) in northern Europe (e.g. Netherlands).
An atypical pulmonary carcinoid tumor is a more aggressive variant of a pulmonary carcinoid tumor. They are less common and considered intermediate grade neoplasms and have the same “carcinoid morphology,” but with mitotic rates increased (at 2–10 mitoses per 2 mm2) where the tumor might also be...
A primary pulmonary meningioma is a very rare form of an ectopic meningioma.
They are generally asymptomatic and incidentally discovered although rarely patients with symptoms have also been reported.
Histologically, they comprise of whorls of spindle cells in...
An ectopic meningioma (or primary ectopic meningioma) refers to rare situations where a meningioma arises outside the dura without any connection to the dura, distinguishing it from meningiomas with extracranial or extraspinal growth.
Ectopic meningiomas can occur at vari...
Typical pulmonary carcinoid tumors are considered the more common and more benign low grade form of peripheral pulmonary carcinoid tumors. There is little or no known association between typical carcinoid tumors and tobacco use or exposure to other carcinogens which contrasts to atypical carcino...
Vascular invasion in lung cancer is one of the invasive patterns that can occur in lung cancer. Dependent on the publication, this could mean:
intratumoral vascular invasion (IVI)
microscopic vascular invasion (MVI)
lymphovascular invasion (LVI)
Tumor spread through air spaces (STAS) is a relatively recently recognized pattern of invasion in lung adenocarcinoma. According to the 2015 WHO classification, STAS is defined as “micropapillary clusters, solid nests, or single cells spreading within air spaces beyond the edge of the main tumor...
Human epidermal growth factor receptor 2 (HER-2) mutations may be detected in approximately 3% of lung adenocarcinomas 1.
Early studies have suggested HER2-mutant tumors exhibit more aggressive features in general and tend to:
exhibit a locally-invasive behavior comp...
KRAS (shortened name for the gene Kirsten RAt Sarcoma viral oncogene homolog) mutations are associated in a number of malignancies including:
certain adenocarcinomas of the lung
colorectal carcinoma 1
pancreatic ductal adenocarcinoma
Several germline KRAS mutations have also been found to b...
An epidermal growth factor receptor (EGFR) mutation may be expressed in a large proportion of non-small cell lung carcinomas (NSCLC). However, certain subtypes such as invasive mucinous adenocarcinoma of the lung can have very low expression.
The presence of this mutation can be assessed on bio...
Esophageal and esophagogastric junction adenocarcinoma staging refers to TNM staging of adenocarcinoma originating in the esophagus or esophagogastric junction (including tumors whose center is within the proximal 2 cm of the gastric cardia).
Related histologies included in this system are high...
Anaplastic lymphoma kinase (ALK) gene rearrangements are known to occur in association with several tumors. The genes code for an enzyme called anaplastic lymphoma kinase (ALK) or ALK tyrosine kinase receptor (also known as CD246) which is thought to play a role in brain development and exerts i...
Metachronous primary lung carcinoma usually refers to tumors with the same histology which are "separated in time" when there has been a disease-free interval between cancers.
Its definition has been "variably" defined in the literature and can include:
time interval of at least 2 years or the...
Pulmonary interstitial glycogenosis (PIG) is a rare pediatric interstitial lung disease associated with alveolar growth abnormalities.
Patients may present in the neonatal period with disproportionate respiratory distress (neonatal respiratory distress).
Thyroid transcription factor 1 deficiency is a situation characterized by mutations in the gene encoding thyroid transcription factor, NKX2-1.
It can result in neurological, thyroid, and pulmonary dysfunction (including neonatal respiratory distress). Children can have a range of mil...
Thyroid transcription factor 1 (TTF1) refers to a homeodomain-containing nuclear transcription factor that belongs to the Nkx2 gene family encoded by a gene located on chromosome 14q13.
It is expressed in the forebrain, thyroid and lung tissues. The presence of TTF-1 protein on a tissue sample ...
Programmed death-ligand 1 (PD-L1)-targeted monoclonal antibodies interact with a protein called PD-1 on T-cells and can be useful in determining if certain immunomodulation therapies can be used in treatment of certain types of cancers. PD-L1 is a major immune checkpoint protein that mediates an...
Endobronchial lipomatous hamartoma is a type of hamartoma, found in the conducting airways, that can be considered as a variant of endobronchial hamartoma, with a predominant lipomatous component. In general endobronchial hamartomas are thought to contain more fat than parenchymal pulmonary ham...
Diaphragmatic dysfunction is a rather broad descriptive term that can include:
diaphragmatic paralysis (can range from complete to partial)
Other conditions that can be variably associated with dysfunction include:
diaphragmatic elevation / hemidiaphragmatic elevation
Thoracic pleomorphic adenoma can include:
pleomorphic adenoma that has metastasized to the lungs
primary pulmonary pleomorphic adenoma - extremely rare 1
primary pleomorphic adenoma of bronchial/tracheal origin - extremely rare 4,5
Historically pleomorphic adenomas have also ...
Excessive dynamic airway collapse (EDAC) refers to a dynamic form of central airway obstruction characterized by a decrease of ≥50% (more recent publications suggest >70%) in the cross-sectional area of the tracheobronchial lumen. Diagnosis is usually confirmed by dynamic cross-sectional imaging...
Fibrosing organizing pneumonia is a term usually given in a situation to cases with previous organizing pneumonia which progresses with a fibrotic component. Many of these cases tend to be those of secondary organizing pneumonia.
Diaphragmatic mesothelial cysts are rare benign congenital lesions involving the diaphragm. They are thought to derive from celomic remnants.
They typically present in the pediatric population.
Typically right-sided and seen as a cystic mass between th...
Clothing artifacts, like jewelry artifacts, are a regular feature on imaging examinations, especially plain radiographs, but in general are recognized for what they are, either at the time the image is taken by the radiographer, or later by the reporting radiologist. The radiographer will often ...
Chronic exogenous lipoid pneumonia is a subtype of exogenous lipoid pneumonia.
Typically occurs in older patients but also has been reported in children as well as infants with usage of mineral oil as a lubricant to facilitate feeding. Can occur in patients without a predisposing...
Anti-Jo-1 antibody positive interstitial lung disease refer to cases of interstitial lung disease occurring in the setting on anti-Jo-1 antibody positivity.
Anti-Jo-1 antibody positivity has a recognized association with interstitial lung disease. This most commonly occurs in a setti...
Intravenous drug users (IVDU), also known as intravenous drug abusers (IVDA), are patients who inject recreational drugs, most commonly heroin, although many other agents are frequently injected, including cocaine, prescription opioids and methamphetamine.
Intravenous drug users f...
Rapidly progressive interstitial lung disease (RP-ILD) is a temporal descriptive term for forms of interstitial lung disease that can progress rapidly through time. A consensus on the temporal time frame, however, has not been published at this time. There is also no clear morphological descript...
Anti-MDA5 antibody-positive amyopathic dermatomyositis is a subtype of dermatomyositis where there is positivity to an anti-melanoma differentiation-associated gene 5 (MDA5) antibody. It has been reported to be associated with rapidly progressive interstitial lung disease (RP-ILD) resulting in h...
An interstitial lung abnormality (ILA) is an imaging descriptor often encapsulating several imaging patterns of increased lung density / attenuation detected on chest CT scans in patients with no prior or established history of interstitial lung disease.
It is considered a relative...
Quantitative computed tomography (QCT) in thoracic imaging has multiple potential applications although often not adopted in standard use in many centers at time of initial writing (2019). These include
quantitating lung intensity / density and airway geometry in the normal adult human lung
Quantitative computed tomography (QCT) can refer to
quantitative computed tomography - bone (in BMD assessment)
quantitative computed tomography - thoracic imaging
Smoking-related interstitial lung disease (SR-ILD) refers to a subgroup of interstitial lung diseases that fall under smoking-related lung disease. Conditions that can fall into this group include.
respiratory bronchiolitis (RB)
respiratory bronchiolitis ILD (RB-ILD)
Familial Mediterranean fever (FMF) (also known as recurrent polyserositis) is a genetic autoimmune condition that is notable for its spontaneous self-limiting acute episodes of fever and serositis, especially peritonitis and synovitis.
Familial Mediterranean fever tends to be ethn...
Community-acquired pneumonia (CAP) refers to pneumonia caused by an infectious agent that is contracted in the general population, and not whilst in a medical facility, or from contact with the healthcare system. A diagnosis of CAP may still be reached up to 48 hours post-admission to hospital 2...
Decompression illness (DCI) results from a reduction in the pressure surrounding a body. It can occur in divers, compressed air workers, aviators and astronauts.
Diving-related decompression illness is classified into two main categories:
arterial gas embolism (AGE) secondary to pulmonary deco...
Amyloidosis involving the pleura is a very uncommon manifestation of thoracic amyloidosis estimated to only occur in 1-2% of patients with systemic amyloidosis 1.
Non-specific and when present, pleural amyloid involvement has typically been discovered due to recurren...
Thoracic amyloidosis can have different manifestations depending on the specific anatomic site:
nodular parenchymal amyloidosis
diffuse parenchymal amyloidosis
A pleurobiliary fistulae refers to an abnormal fistulous communication between the biliary tree and pleural space. It forms the large portion of thoracobiliary fistulas and can occur in various situations such as with complications secondary to trauma, infection, malignancy, biliary disease, or ...
Sulfasalazine lung toxicity is a rare and poorly understood entity, usually taking the form of eosinophilic pneumonia, for which only a handful of case reports can be found in the literature.
Unknown but probably very rare. Occurred twice in a series of 774 patients treated with s...
Prone high-resolution CT (HRCT) chest corresponds to an additional CT acquisition performed as part of an HRCT chest protocol. It represents a scan performed with the patient in a prone position and images obtained in full inspiration.
This additional imaging is particularly useful for detecti...
High-resolution CT (HRCT) of the chest, also referred to as HRCT chest or HRCT of the lungs, refers to a CT technique in which thin-slice chest images are obtained and post-processed in a high-spatial-frequency reconstruction algorithm. This technique obtains images with exquisite lung detail, w...
Potato nodes are a classical moniker for the large nodes seen in the lung hila and mediastinum on the chest radiograph in pulmonary sarcoidosis. This name is derived from the characteristic bulky irregular morphology of the nodes which is reminiscent of large lumpy potatoes. Although this appear...
Lactate dehydrogenase (LDH or LD) is a key enzyme in most cells, catalyzing the reversible conversion of pyruvate to L-lactate. Its contemporaneous main clinical uses are limited primarily to the investigation of hemolysis, serous collections and as a tumor marker.
The "cluster of black pearls" sign refers to a finding on contrast-enhanced CT useful in differentiating sarcoidosis from other causes of lymphadenopathy such as tuberculosis, lymphoma and metastatic adenocarcinoma.
The sign is depicted by the presence of multiple tiny round nodules (1-2 mm) di...
The empty cyst sign is described in hydatid disease. After rupture of the cyst and complete evacuation of its content, the pericyst becomes empty as an air-filled cyst on x-ray or CT 1,2. With superadded infection, an air-fluid level may appear within the cyst, mimicking a lung abscess 2.
The crescent sign is described in hydatid disease. When the hydatid cyst erodes the adjacent bronchus or bronchiole, the trapped air between the pericyst and the laminated membrane of the endocyst gives a crescent-shaped rim of air around the cyst, thus is termed the crescent sign 1,2. It can b...
The serpent sign, a.k.a. snake sign, is described in hydatid disease. The WHO classification (2001) or Gharbi classification (1985) of hydatid disease describe several stages on ultrasound 1.
During the active stage, the cyst is composed of three layers: the outer (pericyst), the middle (ectocy...
The suspected foreign body inhalation series although not a primary port of investigation aims to detect and identify both foreign bodies or the secondary signs of inhaled foreign bodies 1. It involves a frontal chest radiograph in both the inspiration and expiratory phases and, in some cases, b...
The egg and banana sign is a sign for the diagnosis of pulmonary arterial hypertension (PAH) on axial CT/MR images. It refers to the appearance of the aortic arch (banana) next to a distorted main pulmonary artery (egg). Like an egg, the main pulmonary artery is preferentially dilated in the PA ...
A reticulonodular interstitial pattern is an imaging descriptive term that can be used in thoracic radiographs or CT scans when are there is an overlap of reticular shadows with nodular shadows. This may be used to describe a regional pattern or a diffuse pattern throughout the lungs.
Pulmonary tumor embolism refers to a specific type of pulmonary embolism where the embolic constituents comprise of tumor components/particles or tumor thrombus. It can either be microscopic or macroscopic.
Microscopic tumor embolism
Thought to occur from two distinct pathophysiolog...
Pyrexia (or fever) is a clinical sign, indicated by an abnormally elevated core body temperature, which is defined by several medical societies as ≥38.3°C (≥≈101°F). The temperature elevation may be persistent or episodic. If the body temperature is greater than 41.5°C - a rare phenomenon - it i...
Leukemic cell lysis pneumopathy, also referred to as acute lysis pneumopathy, refers to an acute respiratory failure that can occur in patients with leukemia after the initiation of chemotherapy, particularly in those with hyperleukocytosis. On imaging, it manifests with features of acute respir...
Felix Fleischner (1893-1969) was a renowned chest radiologist who had two distinguished careers, first in Vienna, before the Second World War, and secondly in Boston, Massachusetts, after fleeing Europe in 1938. The Fleischner Society was named in dedication to him.
Felix George Fle...
The doughnut sign can refer to various imaging appearances:
crescent in a doughnut sign (bowel)
doughnut sign (bone scan)
doughnut sign (bowel)
doughnut sign (chest)
doughnut sign (missed testicular torsion)
doughnut sign (orbit)
Papillary muscle calcification in the heart in small amounts can be a common finding in elderly patients and are often located at the apex. Large calcifications involving the papillary muscles are, however, rare. They have been associated with conditions such as:
coronary artery disease
The jellyfish sign refers to the sonographic appearance of atelectatic lung "swimming" within a large pleural effusion. The mobility of the lung within pleural fluid implies an absence of lung consolidation and the absence of pleural adhesions 1. It is also suggestive of a transudative pleural e...
Aortic valve calcification can be an important incidental observation in thoracic radiography or CT imaging. It is considered a marker for clinically significant aortic stenosis.
According to some reports, aortic valve calcification may be prevalent as an incidental finding in up ...
Psittacosis, also known as ornithosis, refers to a disease caused by the organism Chlamydia psittaci, which is transmitted to humans predominantly from birds.
Occupations such as bird owners, veterinarians, breeders and sellers of birds, and commercial poultry processors are consi...
Esophagitis refers to inflammation of the esophagus.
Esophagitis can arise from a range of causes which include:
acute phlegmonous esophagitis
The ginkgo leaf sign can refer to:
ginkgo leaf sign (chest) of chest wall surgical emphysema
ginkgo leaf sign (spine) of spinal meningioma
The pectoral region is the anterior region of the upper chest where there are four thoracoappendicular muscles (also known as the pectoral muscles):
The breast is located superficial to the muscles. The lateral border of the pec...
Metal fume fever is a (typically) self-limiting disease due to exposure to fumes emanating from working metal, e.g. welding. Polymer fume fever is a related, yet distinct, condition.
Due to gradual improvements in health and safety over the past 100 or so years, a marked decline i...
Beryllium (chemical symbol Be) is an alkaline earth metallic element, that has no known function in any organism. Unfortunately beryllium is very poisonous, manifesting as chronic beryllium lung disease, which causes premature mortality in one third 1.
Beryllium is a...
Linear atelectasis (plural: atelectases), and also known as discoid, plate or band atelectasis, refers to a focal area of subsegmental atelectasis that has a linear shape. Linear atelectasis may appear to be horizontal, oblique or perpendicular and is very common. It usually occurs as a conseque...
The deep sulcus sign can refer to two different radiographic signs but is best known in the chest:
deep sulcus sign (chest): of pneumothorax on supine CXR:
deep sulcus sign (knee): better known as the lateral femoral notch sign of ACL injury
Gravity-dependent atelectasis refers to a form of lung atelectasis that occurs in the dependent portions of the lungs.
Gravity-dependent atelectasis occurs due to a combination of reduced alveolar volume and increased perfusion. Due to gravity, it usually has a dependent and subpleur...
Thoracic duct embolization (TDE) is a safe, efficacious treatment for chylothorax 1. Chylothoraces with a low drain output (<1L/day) are traditionally managed conservatively with dietary change, whilst high output (>1L/d) are managed with surgical thoracic duct (TD) ligation 2.
Thoracic duct em...
Compressive atelectasis refers to a form of lung atelectasis due to compression by a space-occupying process.
Some authors describe it as a subtype of passive (relaxation) atelectasis where the reduction in lung volume is greater than its normal relaxed state 1. Whereas others describe it as th...
Passive atelectasis, also known as relaxation atelectasis, refers to a form of lung atelectasis due to loss of the negative pressure state in the pleural space. With a loss of the negative intrapleural pressure, the lung is no longer held against the chest wall and is said to relax back to its n...
Adhesive atelectasis refers to the specific form of lung atelectasis that occurs due to the decrease or absence of pulmonary surfactant produced by type II pneumocytes. Without sufficient surfactant the alveoli collapse due to increased surface tension. It is most commonly seen in neonates with ...
The antler sign is an uncommon sign of lung torsion on CT where branches from the main pulmonary artery all arise from a single side, indicating twisting of the lobe or lung.
In the normal lung, the main pulmonary arteries are straight and lobar and segmental branches arise from it on both side...
Benign asbestos-induced pleural effusions are considered part of asbestos related benign pleural disease.
Patients may be asymptomatic or present with dyspnea or chest pain.
They develop after an extended latency period post-asbestos exposure, with a median du...
The pericardial fat tag sign is a sign of pneumothorax on supine CXR where the cardiac border has a lumpy contour.
When gas is located in the pleural space between the lung and mediastinum, the pericardial fat is no longer compressed against the mediastinum and therefore can hang or dangle late...
Lobar consolidation is the term used to describe consolidation in one of the lobes of the lung. It infers an alveolar spread of disease and is most commonly due to pneumonia.
Consolidation refers to the alveolar airspaces being filled with fluid (exudate/transudate/blood), cells (inf...
Left lower lobe consolidation refers to consolidation in part (incomplete) or all (complete) of the left lower lobe.
Consolidation refers to the alveolar airspaces being filled with fluid (exudate/transudate/blood), cells (inflammatory), tissue, or other material.
The list of causes...
A buffalo pneumothorax (or buffalo chest) refers to the rare occurrence of bilateral pneumothoraces caused by an abnormal physical communication between the two pleural spaces. The pleuropleural communication is postulated to be in the anterior median chest where there is a loss of the normal an...
Left upper lobe consolidation refers to consolidation in part (incomplete) or all (complete) of the left upper lobe.
Consolidation refers to the alveolar air spaces being filled with fluid (exudate/transudate/blood), cells (inflammatory), tissue, or other material.
The list of cause...
Right upper lobe consolidation refers to consolidation in part (incomplete) or all (complete) of the right upper lobe.
Consolidation refers to the alveolar airspaces being filled with fluid (exudate/transudate/blood), cells (inflammatory), tissue, or other material.
The list of caus...
Pleural effusions in pulmonary embolism are thought to be the fourth commonest cause of pleural effusions.
The pleural fluid is almost always an exudate 2. The presence of pleural fluid is however not thought to be directly due to infarction 7.
They usually oc...
An endobronchial hemangioma is a rare benign lesion that can occur in the tracheobronchial tree.
Patients may present with hemoptysis and cough.
Endobronchial hemangiomas may appear occultly on chest radiographs. Commonly appear as circumscribed le...
A useful mnemonic to remember the causes of calcifying pulmonary metastases is:
B: bone (chondrosarcoma, osteosarcoma)
A: any primary post-chemotherapy
T: thyroid and testis
Another useful mnemonic is BOTTOM.
A useful mnemonic to remember the causes of interstitial lung diseases which do not cause volume loss is:
E: eosinophilic granuloma (pulmonary Langerhans cell histiocytosis)
N: neurofibromatosis type 1
T: tuberous sclerosis
A stove-in chest is a rare and complex type of flail chest injury where the flail segment collapses into the chest. It is usually due to severe blunt trauma to the chest wall and is rarely encountered in imaging or emergency medicine due to the high mortality at the scene. It may evolve over day...
A useful mnemonic to remember the complications of pulmonary interstitial emphysema is that the most common ones begin with:
Calculating the chemical shift ratio (CSR) is one way of differentiating benign thymic tissue from thymic neoplasms 1:
CSR = (tSIopp / mSIopp) / (tSIin / mSIin)
in = in phase, m = muscle, opp = opposed phase, SI = signal intensity, and t = thymus
Using a cut-off if 0.849, CSR is 100% specific...
The plankton sign refers to swirling, punctiform internal echoes within an otherwise anechoic pleural effusion which demonstrate slow, whirling dynamics, occasionally buffered by cardiac and respiratory impulses. When present, one may rule out a transudative effusion, and should be highly suspic...
Lymphoid thymic hyperplasia, also referred to as lymphoid follicular thymic hyperplasia or autoimmune thymitis, is a form of thymic hyperplasia.
This condition is most commonly associated with conditions, such as:
myasthenia gravis: may be se...
Acute pulmonary schistosomiasis refers to the acute form of pulmonary schistosomiasis.
The acute form commonly occurs approximately 6 weeks after the infection and is thought to represent an allergic manifestation to the presence of Schistosoma worm or eggs.
Pulmonary schistosomiasis refers to lung involvement in schistosomiasis. Lung involvement can occur in 50% of cases. It occasionally falls into the group of secondary eosinophilic lung disease.
The disease is broadly categorized into two main forms:
acute: acute pulmonary schistosomiasis
Brachytherapy seed migration to the lung is a known complication of radioactive seed therapy. These seeds are used for localized treatment of malignancies, most commonly prostate cancer.
Regarding staging, nearly 79% of the cases are localized, 12% are regional and 5% present with distant disea...