Lung cancer Flashcards
Scenario: 70 yr old smoker, COPD with small cell lung cancer. Histology report saying carcinoid invading pleura and lymph nodes
What are the signs of aggressiveness of tumour?
-Lymph nodes
-Invading pleura
What is the pathogenesis of clubbing?
Various hypotheses have been propsed
–> some research found significantly higher plasma growth hormone levels in patients with lung carcinoma and clubbing than patients without clubbing
–> platelet clusters lodged in the peripheral vasculature of the digitis release platelet derived growth factor and lead to the vascularity, permeability and connective tissue changes that are the hallmark of clubbing
Pancoast paraneoplastic syndrome, what hormones?
ACTH causing cushing’s syndrome
What is the technique for FISH?
-Fluorescence in situ hybridisation
-Cytogenetic technique which uses fluorescent probes binding part of the chromosome to show a high degree of sequence complementarity
-Fluorescence microscopy can be used to find out where the fluorescent probe bound to the chromosome
Scenario: 70 yr old smoker, COPD with small cell lung cancer. Histology report saying carcinoid invading pleura and lymph nodes
6 months later the patient returned with back pain. Why?
Bone metastasis
Define an adenocarcinoma
A cancer that forms in mucus secreting glands throughout the body. The disease may develop in many different parts of the body, but is most prevalent in the following cancers:
-Breast
-Lung
-Colorectal
-Prostate
-Pancreatic
Define emphysema
Emphysema is a lung condition that causes shortness of breath. In people with emphysema, the alveoli are damaged. Over time, the walls of the alveoli weaken and rupture, creating larger air spaces instead of many small ones
What are paraneoplastic syndromes?
Symptom complexes that occur in patients with cancer and that cannot be readily explained by local or distant spread of the tumour or by the elaboration of hormones indigenous to the tissue of origin of the tumour are referred to as paraneoplastic syndromes
Give some examples of paraneoplastic syndromes
-The most common paraneoplastic syndromes are hypercalcaemia, cushing’s syndrome and hypercoagulability (including venous thrombosis, non bacterial thrombotic endocarditis)
-The neoplasms most commonly associated with these and other syndromes are lung and breast ca, as well as haematologic malignancy
-Other manifestations are clubbing of the fingers and hypertrophic osteoarthropathy in patients with lung carcinomas
Describe most common cancers and mechanism associated with hypercalcaemia as paraneoplastic syndrome
Cancers
–> SCC of lung
–> Breast ca
–> RCC
–> Adult T cell leukemia/lymphoma
Mechanism
–> parathyroid hormone-related protein
–> TGF alpha
Describe most common cancers associated with cushing’s and mechanism
-SCC of lung
-Pancreatic ca
-Neural tumours
Mechanism
–> ACTH or ACTH like substance
Scenario: a young indian lady came back from foreign travel with cervical lymphadenopathy (anterior triangle mass), loss of weight, night sweats.
What is the differential diagnosis?
-Hodgkin’s lymphoma (more in this age group and involves cervical lymph nodes more commonly)
-TB
Scenario: a young indian lady came back from foreign travel with cervical lymphadenopathy (anterior triangle mass), loss of weight, night sweats.
Which labs will you send her sputum to?
-Microbiology and cytology labs
What are the tests for TB?
-Sputum examination (culture, ziehl Neelsen stain)
-Mantoux test
-PCR to differentiate mycobacteria tuberculosis from other species
-QuantiFERON (interferon gamma assays)
-FNAC of lymph node
How would you label the sputum specimen?
-Category-B UN3373 (infectious substance)
Where would you put the sputum sample?
-In biohazard bag
What organisms can cause TB?
-Mycobacterium tuberculosis
-Mycobacterium avium intracellulare (MAC)–> disseminated infection in immunocompromised patients
-Mycobacterium bovis
What are the culture media for mycobacteria?
-Solid media: lowenstein jensen media, middlebrook media
-Liquid media: BACTEC/MGIT (mycobacteria growth indicator tube)
How long would you culture the sputum?
-1-8 weeks
What type of protein deposition would you get in TB?
Amyloid
Given FNAC result: (necrotic tissue, histiocytes, giant cells), interpret?
TB
What are giant cells?
-Multinucelated cells comprising of macrophages often forming granuloma (e.g. langerhans giant cells, reed sternberg cells)
What would the public health concerns be?
- Notify the consultant in communicable disease control
- Avoid working in a food factory
- Use mask during sneezing or coughing
- DOTS (directly observed treatment, short course) anti TB therapy
- Contact tracing: the identification and diagnosis of persons who may have come into contact with an infected person
What is your advice to contacts?
-Counselling, screening and treatment of other family members
What is a granuloma?
Organised collection of macrophages fusing to form langerhans giant cells
What are other causes of granuloma?
Infections
-Bacterial (TB, leprosy, syphilis, aspiration pneumonia)
-Parasitic infection (schistosomiasis_
-Fungal infections (Histoplasmosis)
Non infective causes
-Sarcoidosis
-Crohn’s disease
-Rheumatoid arthritis
-Foreign body
What is the pathogenesis of TB?
- Infection begins when mycobacteria reach the alveolar air sacs
- Here they replicate within endosomes alveolar macrophages
- Macrophage attempts to kill mycobacterium but cannot be killed by them due mycolic acid capsule: phagolysosome is ineffective
- Primary infection site in the lung is the Ghon focus: can spread to distant sites from here haematogenously
- Inflammatory cells (macrophages, epitheloid cells, T cells, b lymphocytes, fibroblasts) aggregate to form granulomas with caseous necrosis centrally
- Multinucleate giant cells formed by macrophages
What is a mycobacterium?
-Non motile
-Non-sporulating
-Usually aerobic
-Weakly gram positive (stains very weakly due to waxy cell wall but is genetically similar to gram +ve)
-‘acid fast’: have high content of mycolic acid in cell wall
Where can TB affect in the body?
-Almost anywhere
-90% of cases in the lungs
-20% outside lungs to pleura/cns/lymphatics/GU system, etc
-What is potts disease, in relation to TB?
-TB infection of the spine
-Occurs following haematogenous spread of TB, usually affecting lower thoracic/lumbar spine
-Progressive destruction of bones and intervertebral discs can cause spinal collapse/sharply angled spinal curvature
-Abscesses can form, which cause paraplegia secondary to cord compression or track down to psoas muscle
What is miliary TB?
-Widely disseminated TB throughout the body
-Usually occurs following haematogenous dissemination, is characterised by distinctive pattern seen on CXR with large numbers of tiny opacities widespread throughout the lungs
-Miliary TB may also be found in liver/spleen/pancreas
How is TB diagnosed?
Active TB:
-1. Fluid samples (sputum/bronchial-alveolar lavage) for acid fast bacilli using auramine-rhodamine or ziehl-nielsen staining
- PCR to differentiate m tuberculosis from other mycobacteria and allow testing for multi drug resistance
- CXR and CT chest (and other imaging modalities if looking for extra-pumonary TB)
Tests for latent TB:
- Interferon gamma release assay e.g. quantiferon blood test. More reliable than mantoux
- Immunological tests for latent TB include mantoux test or tuberculin skin test: a small amount of tuberculin is injected into forearm and presence of delayed hypersensitivity reaction is assessed at 48-72 hrs - a positive test can indicate latent TB/previous infection but it can be weakly positrive in people who have had the BCG and can be falsely negative in immunocompromised patients. Strong +ve test can mean active TB
How is pulmonary TB treated?
-Multiple antibiotics:
–> rifampicin, isoniazid, pyrazinamide, ethambutol
Indications for surgery:
–> recurrent or massive haemoptysis
–> bronchopleural fistula
–> aspergilloma within tuberculous cavity
–> multidrug-resistant disease unresponsive to chemothgerapy
What is a granuloma?
-Organised collection of macrophages, which can often fuse to form langerhans giant cells.
-The collection of macrophages is often surrounded by a rim of lymphocytes
Lytic vs sclerotic bone mets
prostate
-sclerotic
lytic
-Breast
-myeloma
-thyroid
-renal cell
