A biopsy is a procedure where tissue samples are removed from a patient with the intentions of diagnosing a disease. Upon removal of the tissue samples, the tissue can be studied under a microscope to determine the biology of the cells. Pathologists use biopsies to determine the behavior of the cell, the biology of the cell, and what type of disease a patient has. In the case of TGCT, biopsy is often necessary to confirm diagnosis when the MRI imaging is unclear.
There are two main ways biopsies are performed: core-needle biopsy or during a surgical procedure.
core-NEEDLE biopsy
During core-needle biopsy, imaging such as a CT or ultrasound is used to guide the needle to tissue of interest. Once near the tumor, the surrounding region of the joint is numbed using a local anesthesia (medicines that temporarily numb the area to prevent pain) and a thin needle is inserted into the tissue of interest allowing a small portion to be removed. Three unique locations of the tumor are commonly removed. This type of biopsy can be done in a hospital or at a doctor's office. This is considered a minimally invasive biopsy, however, there is a small risk of infection and bleeding at the needle insertion site.
Surgical biopsy
During surgery, a tissue sample can be removed allowing a pathologist to identify and diagnose the tumor. This is considered more invasive than a core-needle biopsy and is generally done in a hospital or outpatient facility. This may require the patient be fully sedated under general anesthesia (medicine used to induce a state of unconsciousness, pain relief, and amnesia). With the high accuracy of the core-needle biopsy, surgical biopsies are less common.
For those with small localized TGCT, surgical biopsies may remove the entire tumor (called an excisional biopsy).
