Less common tumors.
Right, so there are several different
types of tumours that can present with lung
mass which isn’t a lung cancer. There are
numerous different types, I have discussed
three different types here today. They are
often asymptomatic, nodules on a chest x-ray
or they cause a bronchial obstruction with
cough, haemoptysis or lobar collapse. They
are not related to smoking and the patients
tend to be younger than those who normally
get lung cancer.
So probably the commonest ones are the
carcinoid tumours. These are semi-malignant
that means that they are not fully benign.
They can spread and invade. They don’t tend
to metastasize too much. But they are quite
hard to treat because they do comeback after
resection. They originate from neurosecretory
cells of the bronchial mucosa. They tend to
be central causing bronchial obstruction problems.
Hamartomas are peripheral benign tumours that
show up on chest x-ray, this is a CT scan of
one. They have a distinctive CT appearance
which is a little bit difficult to show on the
scan but essentially they have variable tissues
and types and that means they have variable
density of the nodule on the CT scan.
Another semi-benign, semi-malignant tumour
is adenoid cystic carcinomas which are of
the large airways and again those are treated
by surgical resection.
Metastases to the lung. We have discussed
lung cancers. We have discussed mesothelioma
which are definitely the predominant primary
lung cancers. However the lungs are the site
of metastases from many other tumours very
frequently. So about 50% of patients with
any type of malignant tumour will have lung
involvement usually towards the end stage
of the disease. It will represent stage 4 disease
i.e. incurable disease. For most situations,
there are exceptions. Testicular cancers for
example and lymphomas can be treated even they were
metastasize to the lung. Lung metastases present
with four main patterns.
The x-ray can show masses and these might
be single but usually a multiple, different
sizes both of the lungs and that’s probably
the commonest presentation.
Pleural effusions are also very common and
they have present exactly how you might expect
and the same is a pleural effusion due to
lung cancer with metastases visible on
the pleural, an odd sound on the CT scan that
leads to the increasing size of an effusion
over weeks and makes the patient breathless.
And then you can get mediastinal node involved
just like you do of lung cancer but with
cancers elsewhere in the body, breast cancer,
and prostate cancer for example.
The fourth category is very unusual which
is where you get the lymph vessels being filled
up by the metastatic cancer. This is called
lymphangitic carcinomatosis and this presents
like an infiltration of lung disease with
reticular shadowing on the x-ray and increasing
breathlessness over time.
The important thing about lung metastases is that
they represent stage 4 disease for the primary
cancer. So if you have somebody with breast
cancer and a lung metastases that’s stage
4 incurable breast cancer and the same for
the gastrointestinal tract tumors.
So the lung involvement is key for the treatment
of the primary cancer and that may require
a biopsy to confirm that is the metastases.
Because the implications of treatments for
primary cancer are very important. So the
common cause of lung metastases is
lung cancer itself often metastasizes to other
parts of the lung, same lung and to the different
lung, head and neck cancer, breast cancer,
the gastrointestinal, colorectal cancers,
melanoma, and kidney cancer. The right side shows
the proportion of patients
with these different types of cancer who may
have lung metastases at presentation. So if
a lung cancer for example, nearly a third
of patients will have a lung metastases at
presentation. Kidney cancer 20% of patients.