Runker Room Introduction Frozen Section Cutting In Sign-out Cytology Autopsy Miscellaneous

AP: A Day at the Office Frozen Section Cold, hard decisions Purpose: To provide real-time pathologic assessment of resected tissue When a patient undergoes a procedure (a biopsy or an operation), pathologists usually do not assess the tissue removed until the following day. But sometimes surgeons and clinical physicians ("clinicians") need pathology information more urgently, so they will ask a pathologist for an intraoperative consultation on tissue they have taken out of their patient. While the patient is still in the clinic or under anaesthesia in the operating room, the pathologist will assess the tissue. This involves inspection with the naked eye and, if it is a larger specimen, some dissection. Depending on the surgeon's question and what the pathologist feels is necessary, (s)he may take a frozen section from the specimen and look at it with a light microscope (see sidebar). Indications (reasons) for an intraoperative consultation include: Diagnosis (What is it?) Despite advances in imaging technology (CT and MR scans, ultrasound), patients will often enter the operating room with a differential diagnosis (list of possibilities) of what they have, rather than a definitive diagnosis (a single, confirmed diagnosis). Sometimes the kind of operation a patient needs depends on the type or extent of lesion they have. Before proceeding, the surgeon will take a biopsy of the tissue in question (e.g. a piece of the lesion or a lymph node). The pathologist then provides a preliminary diagnosis that identifies the lesion, or at least narrows down the possibilities. This helps the surgeon decide how much and where (s)he should cut. Assessment of surgical resection margins (Did we remove all of the lesion?) Surgeons don't want to have to go back after sewing the patient up! Before the surgeon closes his/her incision, the pathologist examines the resected tissue to ensure that the lesion is completely excised. Apportioning for special studies Most pathology diagnoses are made by examining formalin-fixed tissue with the naked eye and light microscope, so most specimens are put in formalin-filled containers in the clinic or operating room and sent on to the pathology department for routine processing. Certain situations call for the tissue to be put in special fixatives (e.g. B5 solution for suspected lymphomas, gluteraldehyde for electron microscopy), or no fixative at all (e.g. special tests like flow cytometry, cytogenetics require fresh, non-fixed tissue). The pathologist ensures that the tissue goes to the appropriate special lab. Harvesting for research studies Many modern research protocols require fresh or snap-frozen tissue. Involving the pathologist in the harvesting process ensures that the tissue is actually from the lesion and is viable. The pathologist will also leave enough of the lesion in the specimen to allow a diagnosis to be made. Sorry, this page is still Under Construction Please come again soon! Questions/Feedback thiruki@ipns.com Why so cold? The cellular and nuclear features of section (slice) of a piece of tissue can be discerned by light microscopy when it is cut thin enough to allow light to pass through it. Pathologists usually look at microscope slides made from formalin-fixed tissue embedded in paraffin wax. The wax hardens the tissue so sections can be cut to a thickness of 4-5 microns. But tissue must go through overnight processing to make such a "permanent" paraffin section. In urgent situations like an intraoperative consultation, fresh, unfixed tissue can be frozen to make it hard enough to cut thin sections. How is a frozen section made? A cryostat, a special microtome (fancy mechanical knife) refrigerated to -20 C, is used to cut a frozen section, which is put on a glass slide, stained and coverslipped for examination under the microscope. The whole process, if all goes well, takes 5-10 minutes (NOTE: This is just to make the slide; the time the pathologist takes to look at it under the microscope and arrive at diagnosis is in addition to this).

Introduction | Frozen Section | Cutting In | Sign-out | Cytology | Autopsy | Miscellaneous