Frozen section examination is based on the frozen section of a sample taken during a patient's surgery. This method is used when a diagnosis remains elusive despite all preoperative procedures, or to monitor and determine the progress of the procedure during surgery (for example, to determine whether the tumor has been completely removed). The sample sent during surgery is examined under the observation of a pathologist and the tissue is frozen and examined microscopically. The necessary information is then conveyed to the operating surgeon and recorded. Frozen section examination is not an ideal pathological examination; it is a procedure used in emergency situations where no other option is available.