Currently, if a sarcoma is suspected, a radiographic image of the bone or soft-tissue area will be taken to determine if an abnormality exists. Specific tests include plain x-rays, CT (computerized tomography) and MRI (magnetic resonance imaging) scans to show additional characteristics of the tumor. CT scans of the chest and blood tests also determine if the tumor has spread beyond the site of origin. A bone scan (scintigraphy) or PET (positron emission tomography) scan may be used to detect areas of increased bone metabolism and can identify abnormal processes occurring in the bone, including a tumor.
A biopsy is often necessary to identify the type of tumor. In a biopsy, physicians remove a small piece of tissue or bone to be studied under a microscope for the presence of cancer cells. Historically, biopsies were performed by making an incision through skin in the operating room. Now, leading cancer centers use smaller amounts of bone or tissue to make diagnoses, and many biopsies are performed by using a needle. Radiologic scans including computerized tomography (CT), ultrasound, and fluoroscopy guide physicians to place their needle in an area of the tumor with the highest chance of obtaining a diagnosis. Bone and soft-tissue biopsies should be done by a specialist with expertise in sarcomas, to ensure that the biopsy is accurate and done in such a way that later surgical procedures are not compromised. Biopsy samples should be studied by pathologists with expertise in sarcoma diagnosis. Johns Hopkins radiologists are studying MRI-guided biopsies that enhance images of the tissue or bone and may improve the accuracy of sarcoma biopsies.
Sarcomas can spread to the lungs, and chest CT scans are routinely performed after treatment to detect metastasis (spread).