9/23- Pathology Review Flashcards
What are the stage of intrauterine lung develompent? Timeline?
- Embryonic (26d- 5 wks)
- Pseudoglandular (6 - 16 wks)
- Canaliculur (17-28 wks)
- Saccular (29 wks - birth)
- Alveolar (35 wks - ?)
Histo characteristics of canalicular phase?
Immature acinar structures surrounded by supporting framework
- Can see red cells in some small capillaries
Histology of trachea and bronchi?
- Cartilage
- C-shaped in trachea
- Plates in bronchi
- Submucosal glands
- Smooth muscle
- Lamina propria
- Epithelium
What is key to distinguishing membranous from respiratory bronchiole?
Membranous has smooth muscle (more pink surrounding it)
What type of cells are type I pneumocytes?
Squamous epithelial cells
When does surfactant production by type II pneumocytes begin?
Saccular phase (29 wks - birth)
What are Pores of Kohn and Canals of Lambert?
Provide collateral ventilation by connecting adjacent alveoli and bronchioles
What comprises the pulmonary acinus? Function?
Functional unit of gas transfer (because all lined by alveoli; gas transfer can happen anywhere)
- Respiratory bronchiole
- Alveolar ducts
- Alveoli
What is the epithelium in each lung structure/stage?
- Bronchus: ciliated columnar (pseudostratified?)
- Bronchioles: simple epithelial, columnar or cuboidal
- No more goblet cells, submucosal glands, or cartilage (Lose smooth muscle going from Memb -> Resp bronchiole)
What are the three forms of atelectasis?
- Resorption (obstructive), e.g. mucus plugs
- Compressive, e.g. pleural effusion
- Contraction, e.g. tumor (mesothelioma)
What is DAD?
Diffuse alveolar damage
- Form of acute injury
- Histologic counterpart to the clinical process of ARDS
What are the two types/forms of DAD?
1. Exudative (under 1 wk from injury/inciting event)
- Hyaline membranes = histologic landmark! (begin 2d, peak 4-5 d); precipitated plasma protein and debris from sloughed epithelial cells
2. Proliferative (Organizing) (> 1 wk)
- Proliferation of type 2 pneumocytes
- Formation of granulation tissue - Fibrosis
What is seen here?
Exudative phase of DAD/ARDS
What are types of obstructive lung disease? Provide histologic features of each
Asthma
- Goblet cell metaplasia
- Mucus plugs
- Muscle wall hypertrophy
Chronic bronchitis
- Goblet cell metaplasia
- Mucus plugs
- Submucosal gland hypertrophy/hyperplasia
Bronchiectasis
- Permanent dilatation of airways
- Lower lobes
- Destruction of muscle/elastic tissue by inflammation and fibrosis
- Occurs in cystic fibrosis as well as others
Emphysema
- Permanent enlargement of airspaces distal to terminal bronchiole
- Centriacinar in smokers or panacinar in alpha 1 antitrypsin deficiency
What are the histological components of asthma?
Asthma
- Goblet cell metaplasia
- Mucus plugs
- Muscle wall hypertrophy
What are the histological components of chronic bronchitis?
Chronic bronchitis
- Goblet cell metaplasia
- Mucus plugs
- Submucosal gland hypertrophy/hyperplasia
What parts of the acinus does centriacinar emphysema involve? Panacinar?
Centriacinar
- Respiratory bronchiole
Panacinar
- Alveolar duct
- Alveoli
- Begins distally, but may progress to involve respiratory bronchiole
Is centriacinar emphysema upper or lower lobe dominant? Associations? Panacinar?
Centriacinar
- Upper lobe
- Associated with smoking
Panacinar
- Lower lobe
- Alpha 1 antitrypsin deficiency
What are the macroscopic patterns of pneumonia?
- Bronchopneumonia: inflammation centered in the airways and possibly alveolar tissue just around those tissues (very patchy)
- Lobar
Bronchopneumonia can transition to lobar pneumonia if not treated (although some very virulent organisms may start out lobar)
T/F: A single organism can cause either bronchopneumonia and lobar pneumonia?
True
What are the microscopic patterns of pneumonia?
For lobar pneumonia:
- Congestion
- Red hepatization
- Gray hepatization
- Resolution
What are some complications of pneumonia?
- Lung abscess
- Empyema
- Septicemia -> multiorgan abscess
What is seen here?
Bronchopneumonia
- Patchy; around airways
What is seen here?
Lobar pneumonia
What are complications of lung transplants?
- Infections (bacterial, viral, fungal)
- Acute rejection (wks - mos)
- International Working Formulation (A0-A4) grades rejection based on location and predominant cell type (lymphocytes early, neutrophils later?)
- Chronic rejection (3-5 yrs post-op)
- Problem in half of transplants
- Bronchiolitis obliterans = hallmark!; granulation tissue at level of membranous bronchioles: fibrosis +/- inflammation
What are some organisms that frequently cause opportunistic infection (in lung transplants)?
- Aspergillus: 45’ septated branches
- Crytpococcus: budding yeast with clear halo of polysaccharide capsule
- Pneumocystis
- Herpes
- CMV: can have nuclear or even cytoplasmic inclusions
- Histoplasma
What condition/disease involves bronchiolitis obliterans?
- Acute rejection of lung transplant
- Others?
What are the microscopic and gross findings of UIP?
Microscopic:
- Temporal heterogeneity (mature and immature fibrous tissue adjacent)
- Honeycombing; cystic spaces filled with mucin and lined by metaplastic bronchial cells
- Patchy fibrosis
- Subpleural distribution
Grossly:
- Cobblestoning of pleural surface over involved lung
What can cause honeycombing?
- UIP and other interstitial diseases
- Infection
- Radiation
What are the microscopic findings of NSIP?
Microscopic:
- Lymphoplasmacytic interstitial infiltrate
- Architecture preserved!
- Type II pneumocyte hyperplasia
- Temporally uniform fibrosis (in contrast to UIP); no fibroblastic foci
What are the microscopic and gross findings of asbestosis?
Microscopic:
- Patchy interstitial and subpleural fibrosis (fibers stimulate release of mediators leading ot repeated cycles of inflammation/fibrosis)
- Starts around resp bronchioles and alveolar ducts; proceeds distally
- Fibrosis similar to UIP, but should see asbestos bodies! (asbestos fiber + iron-protein coat; look like dumbbell beaded bodies)
- Honeycombing
Grossly:
- Visceral pleural thickening
- Most commonly affects lower lobes
Where do pleural plaques commonly form?
- Parietal pleura
- Domes of diaphragm
What are pleural plaques made of?
Typically acellular; don’t commonly have asbestos bodies
What are the microscopic and gross findings of silicosis?
- Early: dust-filled macrophages, lymphatic/bronchovascular distribution
- Later: silicotic nodules (lamellar fiborsis with birefringent silica particles)
- Uniform fibrosis begins around bronchioles
- Can get honeycombing
Grossly: upper lobes
What are the microscopic and gross findings of HP?
Acute:
- Neutrophils in alveoli and respiratory bronchioles
- Lasts 1-2 days
Subacute/chronic (3 characteristics you need to know!)
1. Interstitial lymphoplasmacytic infiltrate (beings around bronchioles (~100%)
2. Ill-defined, random, non-caseating granulomas (~67%)- these are more diffuse/less discrete than the granulomas of sarcoidosis
3. Patchy organizing pneumonia (60%)
What are the microscopic findings of sarcoidosis?
Microscopic
- Mutliple nodules: pleura, interlobular septa, bronchovascular structures
- Well-formed/defined granulomas:
- Epithelioid histioctyes
- Multinucleated giant cells
- Chronic inflammatory cells
- Usually no necrosis!! (noncaseating)
- Lung architecture preserved
- Must rule out infectious organisms (TB, fungus) before starting to treat sarcoidosis with steroids
What are the microscopic findings of COP?
Microscopic:
- Intraluminal plugs of granulation tissue (Masson bodies) in distal airways (bronchioles, alveolar ducts, alveoli)
- Patchy distribution; temporally homogeneous
- Lung architecture preserved
- Inflammation
What are the microscopic findings of RB?
- Finely pigmented (dusty brown) macrophages in respiratory bronchioles and adjacent alveolar ducts and alveoli
- Lung architecture preserved
- More?
What are the microscopic findings of DIP?
- Diffuse involvement of lung parenchyma
- Large accumulation of alveolar macrophages
- Uniform fibrotic thickening of alveolar septa (mild-moderate)
- Chronic inflammation; overall lung architecture preserved
- No honeycombing
What are the ILDs associated with smoking?
- RB: Respiratory Bronchiolitis
- DIP: Desquamative Interstitial Pneumonitis
How are lung cancers divided?
How does the treatment vary with each?
- Small cell: chemo and radiation
- Non-small cell: start with surgery if resectable
Histological characteristics of squamous cell carcinomas?
- Have stratified squamous organization
- Commonly necrotic; can form —
- Keratin
Histological characteristics of adenocarcinoma?
- Presence of glands
- Mucin production (if no glands seen, may have to stain for mucin)
What are the 2 types of AIS?
Adenocarcinoma in situ
- Mucinous
- Non-mucinous
(Can only say AIS if entire resection and no vascular or septal invasion.. otherwise adenocarcinoma “with lepidic growth pattern”)
Histological characteristics of small cell carcinoma?
- Hyperchromatic cells
- Indistinct nucleoli
- Nuclear indentation/hugging
- Necrosis (?)
Histological characteristics of typical carcinoid tumor?
- Bland looking cells
- Rich vascular tissue
- Chromogranin stain shows NE
Stain for large cell NE tumor?
CD56+
