Gupta - Pathology/Histology Flashcards
What is the pathogenesis of silicosis?
What are the obstructive lung diseases (4)?
- Emphysema
- Chronic bronchitis
- Asthma
- Bronchiectasis
- Lung does not empty; air is trapped
What do you see?
- Example of busulfan toxicity
1. Mild interstitial fibrosis accompanied by:
a. Lymphocytic inflammation and
b. Type II pneumocyte hyperplasia (arrows)
What is drug/radiation pneumonitis?
- A variety of drugs, especially chemotherapeutic agents, can cause pulmonary fibrosis
- Radiation to the chest causes pulmonary fibrosis
What do you see here?
- Liver biopsy showing pink PAS positive hyaline granules
- Pink globules IN the cytoplasm
- Sign of A1AT deficiency -> A1AT is a misfolded mutant protein that accumulates in the endoplasmic reticulum of the hepatocytes (and may even lead to liver cirrhosis)
What do you see here?
Barrel chest: characteristic of emphysema
What is this?
- Gross appearance of bronchiectasis: regardless of the cause, this will be the general gross appearance
- This case shows saccular dilation of the airways (arrows) with surrounding fibrosis
What are the histologic manifestations of chronic bronchitis?
-
Submucosal gland hypertrophy of large airways
1. Increased Reid index (% of submucosa composed of glands) - Increase in goblet cells in smaller airways
- Chronic (lymphocytic) airway inflammation (plasma cells)
1. Acute: neutrophils - Peribronchial fibrosis
What are the arrows pointing to?
- Type II pneumocytes (hobnail-shaped)
1. Post-injury and destruction of normally abundant type I pneumocytes, type II pneumos are the main cell type involved in repair
What is this?
Normal respiratory epithelium
What is this?
Normal lung CT
What are the gross and microscopic findings with IPF?
-
Gross findings:
1. Patchy interstitial fibrosis
2. Predominant lower lobe subpleural distribution -
Microscopic findings (usual interstitial pneumonia):
1. Fibroblast foci
2. Collagenized areas
3. Mild lymphocytic inflammation
4. Intervening areas of normal lung
5. Honeycombing in advanced cases
What do you see here? What are each of the arrows pointing to?
-
Fetal lungs: look VERY DIFFERENT
1. Sacculation
2. Bronchi
3. Pulmonary artery - Saccular stage is where the transition starts to begin making surfactant (26-32 weeks) -> the one to KNOW
- Branching tubes from the foregut give rise to the trachea, bronchi and bronchioles
-
Alveoli start to differentiate around 7 months, and there are 3 stages:
1. Glandular – thick walls, lots of interlobular and intralobular CT and a cuboidal epithelium
2. Saccular stage (26-32 weeks) – transition to flat, type 1 alveolar cells and type 2 cells (surfactant!!)
3. Alveolar stage – reduction of interstitial tissues and increasing capillaries - At birth, the lungs are not histologically “mature” -> this happens around age 8
What is this?
- Paraseptal emphysema (exact cause unknown)
- Distal acini adjacent to interlobular septa and pleura affected
What are pneumoconioses? What are the 4 types?
- Non–neoplastic lung reaction to inhaled dusts (chronic exposure)
- Mineral dusts:
1. Coal
2. Silica
3. Asbestos
4. Berylliosis - Others: chemical fumes/vapors
What is chronic bronchitis? How is it defined?
- Defined clinically -> persistent cough with sputum at least 3 months in at least 2 consecutive years
- Inhaled substances such as tobacco smoke cause chronic irritation resulting in mucous hypersecretion
What is this?
- Giant cell inclusions -> asteroid bodies
1. Not specific for sarcoidosis, and can occur in other granulomatous diseases
What is centriacinar emphysema? What is is characteristic of?
- Affects central portion of acinus while sparing distal alveoli
- Characteristic of the emphysema associated w/heavy smoking (upper lobes)
What is this?
-
Hypersensitivity pneumonitis
1. Plug of organizing pneumonia with accompanying lymphocytic inflammation
What is this arrow pointing at?
Ciliated cells
What are the causes of hypersensitivity pneumonitis?
-
Thermophilic bacterial Ags
1. Farmer’s lung
2. Mushroom worker’s lung
3. Humidifier lung
4. Hot tub lung -
Animal proteins
1. Bird fancier’s lung
2. Mollusk shell HP -
Fungal Ags
1. Malt worker’s lung
2. Cheese washer’s lung
3. Paprika splitter’s lung
4. Maple bark stripper’s lung
What is simple CWP?
- Little/no pulmonary dysfunction
- Upper lobe predominant
- Coal dust macules (1 – 2 mm diameter)
1. Accumulation of dust adjacent to respiratory bronchioles ± dilated adjacent alveoli (localized emphysema) - Coal dust nodules (0.3 – 1 cm diameter)
1. Carbon-laden macrophages with collagen
What diseases other than IPF can show UIP histologically? How does this affect IPF diagnosis?
-
Collagen vascular disease- associated frequently show UIP histologically (see attached image):
1. Rheumatoid arthritis, scleroderma, mixed connective tissue disease, and others - Because UIP can occur in diseases other than IPF, the diagnosis of IPF is one of exclusion
What is atelectasis? What are the 3 types, and what causes them?
- Collapse of previously inflated lung resulting in relatively airless pulmonary parenchyma -> loss of lung volume caused by inadequate expansion of air spaces
1. Resorption: obstruction, i.e. mucus (postoperatively, asthma, bronchiectasis, chronic bronchitis, tumor, foreign body aspiration)
2. Compression: accumulated fluid in pleural cavity, i.e., pleural effusion in CHF, pneumothorax, or elevated diaphragm in pregnancy or ascites
3. Contraction: fibrotic changes - Need to know what kind of a mediastinal shift you are going to get, and what causes it
What is this?
- Complicated CWP
- “Black lung”
- Whole mount thin slice of lung shows pigmented areas of progressive massive fibrosis in the upper lobe (arrows)
What is a T-E fistula? Which one is the most common? What are some acquired causes?
- Failure of the fetal respiratory tract to separate from the GI tract (ventral wall of the foregut) from which it derives can result in tracheoesophageal fistula
1. Branching tubes from the foregut give rise to the trachea, bronchi and bronchioles - Rare, but most common is fistula between lower part of the esophagus and the trachea (top of esophagus ends in a pouch)
-
Acquired causes of TE fistula:
1. Esophageal tumor -> cancer that starts to erode into the trachea
2. Surgery (tracheostomies and NG tubes)
What do you see here?
- Idiopathic pulmonary fibrosis
- Subpleural, net-like reticulations
What is this?
- Microscopic appearance of bronchiectasis
- Airway dilation (arrow) accompanied by surrounding fibrosis and luminal pus
What do you see here? Which one is more pathogenic?
- EM appearance of asbestos
- Among this gp of fiber-forming silicates, types of asbestos that form curly flexible fibers (left) are more easily ingested by macros, and less pathogenic than those that form straight, stiff fibers (right)
What is this?
- Microscopic appearance of chronic bronchitis
- Lymphocytes (arrow) surround the bronchial epithelium
Normal respiratory epithelium. Appreciate it.
Good job!
What is rhinitis?
- Inflammation of the nasal mucosa
- Most commonly attributed to Rhinovirus
- Presents as common cold
- Repeat bouts can create nasal polyps (edema, inflam)
What are these?
- Asbestos bodies
- In addition to macrophage ingestion, the body tries to destroy asbestos fibers by coating them with iron–containing proteinaceous material
1. Results in golden brown beaded rods with translucent fiber cores (arrows)
What do you see here?
- Micro appearance of UIP -> severely affected areas show:
1. Densely collagenized fibrosis (arrows) and
2. Honeycomb cysts lined by metaplastic bronchiolar epithelium (asterkisks)
What are the 3 types of emphysema?
- Centriacinar: associated with heavy smoking, and predominantly in the upper lobes
-
Panacinar: whole acinus, not necessarily the whole lung
1. Associated with α1-antitrypsin deficiency (can’t get out of the liver to go to the lung and protect it)
2. Predominantly lower lung zones -
Paraseptal: on the pleura of the lung
1. Probably underlies spontaneous pneumothorax in young adults
2. Kind of young male who is very tall and thin and comes in with a pneumothorax; get bullous lesions on the edge of the lung that rupture
What is A1AT deficiency?
- Rare cause of emphysema – causes panacinar
- Liver cirrhosis may also be present
- A1AT is a misfolded mutant protein that accumulates in the endoplasmic reticulum (ER) of the hepatocytes
-
Genetics: PiM is the normal allele; two copies normally expressed (PiMM)
1. PiZ and PiS is the most common clinically relevant mutations
2. PiMZ heterozygotes have low levels of circulating A1AT; usually ok unless they smoke
3. PiZZ homozygotes are at risk for panacinar emphysema and liver cirrhosis
What type of atelectasis do you see here?
- Compression pneumothorax
- Left pneumothorax from chest wall trauma resulting in left lung collapse and rightward mediastinal shift
What is asthma? What are the 2 types?
- Chronic inflammatory disorder of the airways
- Increased airway responsiveness to a variety of stimuli
1. Extrinsic: type I hypersensitivity reaction to inhaled allergen
2. Intrinsic: non-immunologic reaction (precipitated by respiratory infection, stress, exercise, cold, drugs like aspirin, etc.)
What is hypersensitivity pneumonitis?
- Immunologically mediated lung disorder due to prolonged exposure to inhaled organic dusts
- Affected individuals abnormally sensitized to antigen in inhaled dust
- Chronic form is a type IV (delayed type) hypersensitivity response
- Progression to fibrosis prevented by removal of environmental antigen
What is the arrow on the left pointing to? What about those on the right?
- Ciliated cells on the left
- Club/clara cells on the right
What is this?
-
Honeycomb lung (via hypersensitivity pneumonitis)
1. Can be caused by persistent exposure to a triggering environmental antigen
2. Represents the end stage of a variety of chronic interstitial fibrosing lung diseases
What is silicosis?
- Caused by inhalation of SiO2 (silica)
- Sandblasters, mine workers, stone cutters: decades of exposure -> progressive nodular fibrosis
- Predominantly upper lobes and hilar nodes
- Silica ingestion by macros causes release of fibrogenic mediators, resulting in hard collagenous nodules
- Polarizing microscopy demonstrates birefringent silica particles
- INC TB susceptibility likely related to impaired macrophage function
What do you see here?
- Gross appearance of paraseptal emphysema
- Markedly enlarged subpleural airspaces, known as bullae (arrow) are prone to rupture -> can result in pneumothorax
What is this?
- Microscopic appearance of panacinar emphysema
- Relatively uniform dilation of all parts of the acini
What is complicated CWP?
- Aka, progressive massive fibrosis
1. Lung function compromised
2. Develops in background of simple CWP over many years -> progression from simple to complicated not well understood
4. Black scars composed of pigment and dense collagen
5. Associated with rheumatoid arthritis
What is the Reid index?
- Ratio of the thickness of the mucous gland layer to the thickness the thickness of the wall between the epithelial basement membrane and cartilage (normal = 0.4) is increased in chronic bronchitis
- Serous (for humidification) and mucinous (to prevent infection) glands
- Anything above 50% counts as an elevated Reid Index
What do you see here?
- Microscopic appearance of asthma
- Asthmatic mucous often has Charcot-Leyden crystals (arrow) formed from the disintegration of eosinophils
1. From major basic protein of eosinophils (if there are enough eosinophils, there will be charcot-leyden crystals) - Mostly going to see these in chronic allergic rhinitis
What is this?
- Hypersensitivity pneumonitis
- Lymphocytic interstitial inflammation and fibrosis centered on a bronchiole (arrow)
What do you see here?
- Microscopic appearance of IPF -> manifests histologically as usual interstitial pneumonia (UIP)
- Features patchy interstitial fibrosis (arrows) that is most severe subpleurally
What is this?
- Microscopic appearance of paraseptal empysema
- Distal airspaces (arrow) immediately beneath the pleural show marked dilation – cause unknown
- Histologically, the location is going to be the most helpful