PathCAL Lung Cancer diagnosis Flashcards
How can X rays be used in investigation?
Chest X ray- white radio-opaque areas
Abnormal shadow has irregular, vague outline
What other radiological scans are useful in investigation?
Computerised tomography
Scan thorax and upper abdomen
What tests do we do to get a definite diagnosis?
Bronchoscopy
Cytology
Endoscopic biopsy
Describe a bronchoscopy
Basically, we have to make a diagnosis by demonstrating malignant cells down the microscope.
We look down the bronchi through a fibreoptic tube which is generically called an endoscope, but in this case is called a bronchoscope.
Through the fibreoptic bronchoscope we can try to obtain a sample of some malignant cells.
This can be done under sedation: the patient can be give a sedative and doesn’t require a general anaesthetic.
In which locations may the tumour be difficult to find?
The upper lobe of either lung.
In the lung tissue outside the bronchi, that is, if it’s extra bronchial.
In either of these locations we might find it difficult to locate the tumour with the endoscope.
What is bronchial brushing?
Rub the surface of the involved bronchus with a small brush, which we remove through the instrument and dab on a glass slide.
What is bronchial washing?
Flush some fluid down the bronchus and remove the fluid through the bronchoscope.
The fluid has washed some neoplastic cells off the main tumour mass and it’s these we’ve collected in the fluid
What problems might arise in using a biopsy for diagnosis?
The tissue fragments are often small and may be traumatised, crushed or fragmented. This may test to the full the pathologist’s skill and expertise.
In addition, such a biopsy may sample only a tiny part of the tumour. Tumours often vary from area to area; it could, for example, be squamous in one area and glandular in another area. So the sampling may give an erroneous impression of the type of tumour. In theory this could lead to the wrong management of the patient, although in practice it’s not as great a problem as it might at first appear.
What are the issues with doing a biopsy or brushing first?
- If the biopsy is done first, the bronchus may bleed and the cytology specimen may become obscured by blood.
- If, on the other hand, the brushing is done first, it may damage the tissue and make the biopsy more difficult to interpret
What are cytological samples not including those from bronchoscopy?
- Sputum: samples are often useful, particularly if the management is less likely to be urgent, for example in elderly patients or in general practice.
- Pleural fluid: If the patient has a pleural effusion, we can tap some of the fluid and send it to the cytologist, who can look for malignant cells.
Describe sputum as a cytology sample
- Sputum cytology has an 80% chance of picking up malignant cells, if they’re there.
- But it’s important to make sure the sample is really sputum and not just saliva or bits of food.
- So the patient has to cough it up from the lungs. Sometimes a physiotherapist may aid the patient to cough it up.
What are the issues with biopsy diagnosis of in situ carcinomas?
The first is that a biopsy may pick up only the superficial epithelium. If there are neoplastic changes in this, it might allow us to diagnose carcinoma in situ. But we couldn’t diagnose invasion with certainty if we didn’t have any of the underlying tissue, such as submucosa.
But often, if there’s a mass on X-ray, we may infer that there must be invasive carcinoma adjacent to the biopsy site. So we can make a diagnosis indirectly.
What are the differential diagnosis of a peripheral lung shadow?
Tuberculosis Infarct Pneumoconiosis Abscess Adenocarcinoma Metastasis
What technique can we use for peripheral lung lesions?
It’s called fine needle aspiration, or FNA for short.
This often enables us to get enough cells for a cytological diagnosis.
Obviously, it requires a bit of skill and expertise to get the needle into the right spot in the chest; so correct sampling is clearly important.
It’s not really termed a biopsy, by the way; in a biopsy the tissue structure is maintained, whereas here the cells tend to be separated from one another, to some degree anyway.
-Insert a needle through the chest wall into the lesion.
-We can suck out some cells with a syringe and squirt them on to a glass slide, then do cytology.
What are the drawbacks of FNA?
- One drawback with FNA is that putting a needle into someone’s chest is no light affair. If, for example, you stuck it into the heart the medical defence union would take a dim view of it.
- On the other hand, it’s difficult to get a needle through bone; so getting at a lesion deep to the scapula is difficult.
- Even if you aspirate material, you still may miss the lesion.
- Or you may pick up inflammatory cells from a neighbouring reaction. This is quite a common problem. So if you get back a report saying there are inflammatory cells, it doesn’t necessarily mean that the patient still doesn’t have a tumour, lurking nearby.
