This page is dedicated to covering the important radiological finding of a solitary pulmonary nodule/mass. Look here for more radiological findings.
WHAT IS IT?
A solitary pulmonary nodule/mass refers to a finding that is often appreciated on a chest X-ray or a chest CT scan. Some distinguish between a nodule and a mass using size: it is thought that a nodule is under 3 cm while a mass is larger then 3 cm. The central question when evaluating a solitary
DIFFERENTIAL DIAGNOSIS FOR THIS FINDING
When seeing a solitary pulmonary nodule/mass, it is important to keep in mind the following possible causes of this finding:
- Granulomas: tuberculosis, histoplasmosis
- Squamous Cell Carcinoma
- Small Cell Carcinoma
- Large Cell Carcinoma
KEY FEATURES TO LOOK FOR WHEN CHARACTERIZING THE FINDING
When seeing a solitary pulmonary nodule/mass, there are a few important radiological features one should look at to try and characterize the finding. These features can help navigate the differential diagnosis above.
Signs Of A Benign Finding:
- Size: smaller nodules are typically less likely to be cancerous (nodules < 4 mm rarely are malignant for example). :
- Stable size (on serial imaging): typically benign lesions will maintain a stable size and not grow when looking at repeat studies.
- Calcifications: the presence of calcifications (in central/laminar/or diffuse patterns) typically is only seen in benign conditions.
Signs Of Malignancy:
- Size: larger masses are much more likely to be cancerous (masses > 5 cm in size are almost always malignant for example).
- Changes in size (on serial imaging): malignant lesions tend to increase in size at a rate that is neither brief enough to suggest inflammatory causes (changes in weeks) nor prolonged enough to suggest a benign nature (no change over a year or more).
- Margins: lobulation, speculation, and irregular margins all are characteristic of malignancy.
Page Updated: 01.09.2017