A biopsy involves taking a small tissue sample for microscopic examination, helping doctors diagnose diseases like cancer. A specialized and rapid type of biopsy is the frozen section, which provides quick information during medical procedures. This technique allows for immediate insights into tissue characteristics while a patient is still undergoing surgery.
Understanding Frozen Section Biopsy
A frozen section biopsy rapidly freezes a tissue sample, typically to temperatures between -20 to -30 °C. This solidifies the tissue without chemical fixation. Once frozen, a cryostat slices the tissue into thin sections, usually 5 to 10 micrometers thick. These sections are then stained and immediately examined by a pathologist under a microscope.
This method differs from a traditional biopsy, which processes tissue over several days using chemical fixation and paraffin embedding. The primary distinction is speed; frozen sections yield results within minutes, while traditional biopsies take much longer. Due to rapid processing, the diagnostic quality of frozen section slides can be slightly lower than those from paraffin-embedded tissue, making it a preliminary assessment rather than a definitive one.
Key Applications of Frozen Section Biopsy
The frozen section technique is employed during surgical procedures to guide medical decisions. One primary use is in oncologic surgery, where it helps determine if a tumor is benign or malignant. This immediate information allows the surgeon to decide the extent of surgery needed, potentially altering the surgical plan.
Another application is assessing surgical margins, which involves checking the edges of the removed tissue for cancer cells. If cancer cells are found at the margins, the surgeon can remove additional tissue during the same operation to ensure complete tumor excision. Frozen sections also identify tissue type or confirm cancer spread to lymph nodes, such as in sentinel lymph node biopsies for breast cancer.
The Frozen Section Biopsy Procedure
The frozen section procedure begins with the surgeon removing the suspicious tissue sample during an operation. This tissue is immediately transported to a pathology laboratory, often located near the operating room. Upon arrival, a pathologist or trained technician prepares the specimen for freezing.
The tissue is placed on a metal chuck and quickly frozen by a cryostat. An embedding medium secures the tissue. Once frozen, the tissue block is sliced into thin sections using the cryostat’s microtome. These slices are mounted on glass slides, stained with dyes like hematoxylin and eosin, for microscopic examination.
A pathologist examines the stained slides under a microscope, analyzing cellular structure and tissue architecture for a rapid diagnosis. Findings are communicated to the surgeon, often via intercom, while the patient is under anesthesia. This typically takes 10 to 20 minutes, allowing the surgeon to make immediate, informed decisions about the remainder of the surgical procedure.
Interpreting Results and Potential Considerations
Results from a frozen section biopsy are preliminary diagnoses, providing rapid guidance during surgery. These findings are often followed by a more definitive diagnosis from a traditional, permanent section biopsy. The permanent section involves more thorough tissue processing, revealing finer details not always visible in frozen sections.
Despite its high accuracy, a definitive diagnosis might not always be possible from the frozen section alone. Freezing can cause artifacts, or distortions, in the tissue, making interpretation challenging. Certain tissue types or complex lesions may also be difficult to diagnose with this rapid method. If the frozen section diagnosis is inconclusive or borderline, the surgeon may proceed with a more conservative approach and await the final permanent section results for definitive treatment planning.