Pathology Flashcards
what are the three types of tumours?
- 4 common smoking associated types
- neuroendocrine tumours
- bronchial gland tumours
what are the 4 types of smoking associated?
- adenocarcinoma
small cell
large cell
squamous
what is the most common one?
adenocarcinoma- it is common in non-smokers too
what does adenocarcinoma often cause on CXR/CT?
peripheral lesions
how does adenocarcinoma arise?
from mucus secreting glandular cells
it metastasises widely
how does squamous carcinoma arise?
from epithelial cells
what are some characteristics of sqaumous carcinoma?
local, slow metastasis
hypercalcaemia
PTH
produces keratin pearls
what problems are often related to squamous ?
bronchiectasis and obstructive pneumonia as the tumour is often centrally located
how does small cell arise?
from APUD cells- these are A GROUP OF unrelated endocrine cells
they secrete ACTH
where is small cell often located?
centrally
on CXR/CT what may be seen with small cell?
hilar mass with extension onto lymph nodes
what are some features of small cell
its hard to treat because of rapid metastasis
what is seen on a slide for small cell?
not much cytoplasm and lots of nuclei. The nuclei look like lymphocytes so it can be confused with lymphoma
what are some characteristics of large cell carcinoma?
pooorly differentiated
metastasis early on
Necrosis and haemorrhage are frequent and there may be acute and/or chronic inflammation. They form large necrotic masses
what is shown on slides for large cell?
it consists of sheets and nests of large cells with prominent vesicular nuclei and nucleoli
The cell borders are easily vascularised.
what may happen to the pleura in large cell?
the large necrotic masses frequently invade the overlying pleura and grow into adjacent structures
what is the pathophysiology of bronchial tumours - i.e. tumours of the lung ?
- squamous metaplasia
- dysplasia
- carcinoma in situ
- invasive malignancy
what happens in peripheral adenocarcinoma
spread of neoplastic cells along alveolar walls (bronchioalveolar carcinoma) without invading underlying stroma.
what are some examples of other lung neoplasms?
carcinoid
bronchial gland neoplasms (tumours often seen in salivary glands)
what are two bronchial gland neoplasms
- adenoid cystic carcinoma
- mucoepidermoid carcinoma
what are carcinoid neoplasms?
neuroendocrine neoplasms of low grade malignancy and they tend to occur in younger patients
what are the pleural neoplasia kinds?
benign tumours are rare
the primary malignant neoplasms - mesothelioma
the pleura is a very common site of invasion of lung carcinomas and metastatic cancers
what would mesothelioma look like on CXR?
usually unilateral, starting as small nodules over the visceral pleura and extending to cover the entire lung
which cancer has the worst and best prognosis ?
small cell is the worst
large cell worse than squamous or adenocarcinoma
squamous worse than adenocarcinoma
why is classification important?
for treatment purposes
- small cell known to be chemosensitive but with rapidly emerging resistance
- surgery is the treatment in other types
for which cancer is pemetrexed contraindicated?
squamous carcinoma
why is classification also quite difficult?
because its hard to subtype tumours on small biopsies
how is immunochemistry often used to help classify biopsies?
in adenocarcinoma - expresses TTF (thyroid transcription factor ) 1
small cell carcinoma expresses nuclear antigen p63 and high molecular weight cytokeratins
what else is used to classify biopsies?
molecular genetic abnormalities
what oncogenes and tumour suppressor genes are expressed in SCLC?
oncogenes- myc
tumour suppressor genes - p53, Rb, 3p
what oncogenes and tumour suppressor genes are expressed in NSCLC?
oncogenes - myc, K-ras, her2 (neu)
tumour suppressor genes - p53, 1q, 3p, 9p, 11p, Rb
Molecular pathology and targeted treatment - Adenocarcinoma
specific point mutations render the EGFR gene active in the absence of ligand (epidermal growth factor) binding
these mutations can be identified in DNA extracted from biopsy or cytology samples
mutations seen almost exclusively in adenocarcinoma (esp. non-smokers and asian populations)
these tumours respond to tyrosine kinase inhibitors (erlotinib)
EML4-ALK fusion oncogene also identifies a target for specific drug treatment (crizotinib)
how are tumours classified?
TNM scale
what does T stand for?
primary tumour 
what does N stand for?
regional nodes
what does M stand for?
distant metastasis
what markers are in stage 1 ?
- carcinoma insitu/ ≤3cm, in lobar or more distal airway/>3cm and >2cm distal to carina or any size if pleural involvement or obstructive pneumonitis extending to hilum, but not all the lung
N0- None involved (after mediastinoscopy)
M0- none
what markers are in stage 2 ?
≤3cm, in lobar or more distal airway/>3cm and >2cm distal to carina or any size if pleural involvement or obstructive pneumonitis extending to hilum, but not all the lung
N1 Peribronchial and/or ipsilateral hilum
M0 none
what are the markers in stage 3a?
Involves the chest wall, diaphragm, mediastinal pleura, pericardium, or 7cm diameter and nodules in same lobe
n1- Peribronchial and/or ipsilateral hilum
M0
or T1-3 N2 M0
what are the markers in stage 3b?
T1-4
T1 ≤3cm, in lobar or more distal airway
T2 >3cm and >2cm distal to carina or any size if pleural involvement or obstructive pneumonitis extending to hilum, but not all the lung
T3 Involves the chest wall, diaphragm, mediastinal pleura, pericardium, or 7cm diameter and nodules in same lobe
T4 Involves mediastinum, heart, great vessels, trachea, oesophagus, verte- bral body, carina, malignant effusion, or nodules in another lobe
N3 Contralateral mediastinum or hilum, scalene, or supraclavicular
M0
