Lung Cancer Flashcards
Lecture notes
Describe structure/airflow of the lungs
- Inhaled air (21% O2) passes down the trachea (windpipe) which branches into two bronchi.
- Each bronchus divides into narrower and narrower branches called bronchi oles
- Bronchioles terminate in alveoli (small cavity air sacs)
Lung tissue H&E shows
- alveoli and alveolar walls: site of O2 and CO2 exchange
- cilliated respiratory epithleium
- bronchiole
- alveoli separated by an interstitium that contains capillaries involved in gas exchange, connective tissue and a variety of cells involved in alveolar shape and defence.
Alveolar lung tissue H&E components and function
twomain stains used for alveolar histology
- Interstitium lined by 2 morphologicallt distinct types of alveolar cells (type 1 and type 2 pneumocytes
type 1: squamous alveolar cells involved in gas exchange
type 2: cubodial alveolar cells involved in modifying surface tension and nehancing macrophage function
Macrophages: defence from foreign substances in the air
Erythrocytes (RBCs)
Reticiulin and H&E stains in alveolus histology
Cell Types in the bronchi and bronchioles
bronchi and bronchioles: ciliated cubodial epithelium and a thin layer of smooth muscle. cells produce mucus trapping particles, cilia moved trapped cells along
main cell types: basal cells, neuroendocrine cells, ciliated cells, serous cells, Clara cells and goblet (mucin producing) cells.
In terminal bronchioles: less globlet and ciliated cells, more Clara cells
Cell types in alveoli
Predominantly squamous alveolar cells (type 1 pneuomocytes) involved in gas exchange
Testing for lung cancer
- Initial testing: via spirometry, blood tests, chest x-rays, CT scans
- Bronchoscopy/biopsy: cells/tissues taken and sent to cellular pathology lab for confirmation of diagnosis and TNM staging
Cell path lab diagnosis
- Samples may be cytological (cells) or histological (tissues) - received by the lab are preserved to maintain morphology
- Processed in the lab to provide a thin layer/section on a glass slide
Viewed under the microscope by a Consultant Respiratory Pathologist - Extra stains/tests requested if necessary to confirm precise type of tumour
Types of lung cancer
Small cell lung cancer (SCLC) & Non-small cell (NSCLC)
Reporting standards
Royal College of Pathologists
Standards and datasets for reporting cancers
Dataset for histopathological reporting of lung cancer
September 2018
Morphological description of small cell carcinoma (SCLC) for typing
- a malignant epithelial tumour derived from neuroendocrine cells of the bronchial epithelium
- cells are round, oval or spindle-shaped with scant cytoplasm and ‘nuclear moulding’, and often show fragmentation and a ‘crush artefact’ in small biopsies
- Immunohistochemistry is positive for neuroendocrine markers
Morphological description of non- small cell carcinomas (NSCLC) for typing
- Adenocarcinoma (NSCLC):
varies with glandular differentiation or mucin production by tumour cells
patterns are acinar, papillary, bronchio-alveolar and solid with mucin formation”. - Squamous cell carcinoma (NSCLC):
range from well-differentiated squamous cell neoplasm with keratin formation and intercellular bridges, to poorly differentiated with only minimal residual squamous cell features. - Large cell carcinoma (NSCLC):
poorly differentiated malignant epithelial tumour consisting of sheets or nests of large polygonal or giant multinuclear cells.
large cell neuroendocrine carcinoma, and confirmation of neuroendocrine differentiation is required using immunohistochemical markers
What is grading? Example of grading levels?
GRADE describes the variation of tumour cell morphology from normal cells
Low grade – slow growing , look similar to normal cells (well-differentiated). Unlikely to spread.
Moderate Grade – look more abnormal (moderate differentiation)
High Grade – faster growing , look very abnormal (poorly differentiated). Likely to spread.
Staging of lung cancer - RCPath TNM - Primary Tumour (T)
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis Carcinoma in situ
T1 Tumour ≤30 mm
T2 Tumour >30 mm but not >50mm
T3 >50 mm but not >70mm
T4 >70mm
Staging of lung cancer - RCPath TNM - Regional Lymph Nodes (N)
NX Regional lymph nodes cannot be assessed
N0 No regional node involvement
N1 Metastasis in ipsilateral peribronchial and/or ipsilateral hilar nodes and/or intrapulmonary nodes (node stations 10–14)
N2 Metastasis in ipsilateral mediastinal and/or subcarinal node(s) (node stations 1–9)
N3 Metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene or supraclavicular nodes
Staging of lung cancer - RCPath TNM - Distant Metastasis (M)
M1 Distant metastasis
M1a Separate tumour nodule(s) in a contralateral lobe; tumour with pleural nodules or malignant pleural or pericardial effusion
M1b Single extra-thoracic metastasis in a single organ and involvement of a single distant (non-regional) lymph node
M1c Multiple extra-thoracic metastases in one of several organs
