Lymphangitis carcinomatosis is an infrequently seen complication of metastatic cancer where cancer invades along the lymphatics channel of the lung causing progressive dyspnoea and cough. Unfortunately it is a sign of progressive disease and although chemotherapy options for the underlying cancer may in some cases slow the progression of disease, there is generally no effective treatment other than good symptom control with opioids and anxiolytics. Steroids sometimes help a little.
Pathogenesis and epidemiology
Lymphangitis carcinomatosis may be the presenting problem in a patient with previously undiagnosed cancer, but more frequently it is a complication that arises in patients who are already known to have metastatic cancer.
The condition develops when malignant cells infiltrate bilaterally into the lymphatics system draining the lungs.
Any cancer can cause lymphangitis carcinomatosis but the most common causes are:
Patients with lymphangitis carcinomatosis generally present with progressive dyspnoea on exertion that develops over a number of weeks or 1 or 2 months. A dry cough is also very common.
On general inspection patients may appear tachypnoeic, tachycardic and cyanosed with low oxygen saturations.
Chest inspection will typically reveal normal percussion, bilateral scattered crackles and normal vocal resonance unless additional chest pathology is present.
Point of care Ultrasound
Bedside point of care ultrasound shows vertical hyperechoic comet tails (or B lines) rather than the normal horizontal hyperechoic A lines of pleural reflection. This is a non-specific sign in chest ultrasound with the two key differentials of pulmonary fibrosis and pulmonary oedema.
- Point of care ultrasound in a man with metastatic renal cell cancer and dyspnoea showing B lines consistent with lymphangitis carcinomatosis
- A still image from the man above with lymphangitis carcinomatosis
- Another still image from the man above with lymphangitis carcinomatosis
Chest x-ray often appears normal but in over half of cases there are some abnormalities noted such as a bilateral reticulonodular shadowing, typically more apparent at the lung bases. Pleural effusions are a relatively common co-existing condition.
Although it is unable to be used to confirm the diagnosis with certainty, CT scanning (especially high resolution CT scanning) is the imaging modality of choice to look for lymphangitis carcinomatosis. Findings include
- A ground glass appearance from interstitial oedema
- Thickening of septa and interstitium
Although CT imaging in context is usually enough evidence to make a diagnosis, if a definitive diagnosis is required, trans-bronchial biopsy can be performed.
If an appropriate chemotherapy regime is available and the patient is well enough, this option should be considered as it is the only treatment that may prolong life and improve symptoms (if it is effective). In many cases the patient will have already had chemotherapy and is known to have progressive cancer with no further chemotherapy options. In these patients, good symptomatic treatment and kind but open discussions about the person's coming end of life are very important.
Steroids may cause a temporary improvement in symptoms, e.g.
Dexamethasone 8mg daily
Movement of air (e.g. with a fan) may help symptoms. In patients with significant dyspnoea with evidence of hypoxia, then palliative oxygen should be prescribed.
For dyspnoea causing significant anxiety and distress, sublingual or subcutaneous benzodiazepines can bring about significant comfort. Regular long-acting and/or PRN immediate release oral opioids may also help.
As a patient with lymphangitis carcinomatosis deterioates, increasing dyspnoea and anxiety are often problems and consideration of a continuous subcutaneous infusion of benzodiazepines and opioids should be considered.