Getting the right diagnosis is key to receiving the best treatment and outcomes. Discovery of thymus cancer often occurs incidentally, through testing such as a chest x-ray or treatment for other conditions such as autoimmune disorders. Diagnosis requires a biopsy, in which a small sample of the suspicious tissue is removed and examined under a microscope. Various ways to diagnose the thymus include:
- Fine-needle Aspiration Biopsy: A thin needle removes a sample of cells.
- Core Biopsy: A wide needle removes a larger sample of cells.
- Mediastinoscopy: A thin, tube-like instrument (mediastinoscope) with a light and viewing lens is inserted through an incision at the base of the neck above the breastbone. Tissue samples can be taken from the thymus and/or nearby lymph nodes.
- Mediastinotomy (Chamberlain Procedure): A tube inserted through an incision on the side of the breastbone is used to view the thymus. A biopsy may be taken from the thymus and nearby lymph nodes.
- Video-assisted Thoracoscopic Surgery (VATS): A minimally-invasive procedure involving only small incisions, through which a tiny camera (thoracoscope) and surgical instruments are passed, allowing surgeons to operate inside the chest, guided by the video transmitted to a monitor. VATS is used for both diagnosing (biopsy) and treating thymus cancers.
Other tests may include:
- Computed Tomography (CT) Scan: X-rays are taken from various angles and assembled by computer to produce detailed pictures inside the body. Sometimes a dye is injected to help certain organs or tissue show up more clearly.
- Magnetic Resonance Imaging (MRI) Scan: A magnet, radio waves and computer are used to create detailed pictures inside the body.
- Positron Emission Tomography (PET) Scan: A small amount of radioactive glucose is injected into a vein and a scanner rotates around the body taking pictures. Malignant cells appear brighter in the scan because they use more glucose.
- Octreotide Scan (OctreoScan): A small amount of radioactive octreotide (a hormone that attaches to certain tumors) is injected into a vein and a special camera captures the radioactivity to reveal the tumor.