Grossing course summary PDF

Preview

Summary

Course Notes – Lecture 1 - Introduction to Specimen GrossingObjectives : Understand how and why grossing specimens are received. Have a basic understanding of handling Cytology specimens. Explain the source of the specimens that are received in the histology laboratory. Be able to classify all t...

Description

1 Course Notes – Lecture 1 - Introduction to Specimen Grossing Objectives:  Understand how and why grossing specimens are received.  Have a basic understanding of handling Cytology specimens.  Explain the source of the specimens that are received in the histology laboratory.  Be able to classify all the specimens received in the laboratory.  Discuss the importance of tracking and labeling pathology material such as blocks, slides, reports, and logbooks. GROSSING -Is the process referred to as grossing a specimen, where tissue specimens taken from routine surgical cases, autopsies, or other scientific investigations are examined, described and trimmed to proper size.  Gross description and dissection of tissue specimens, often referred to as "the gross", is done after tissues are fixed (or partially fixed).  This step precedes tissue processing, embedding, Microtomy and staining. What testing is available in the Histology laboratory? (Gross only and gross & microscopic) 1. “Gross Only” -Is considered for a dictation and report describing the physical appearance of the specimen received. This process may vary from hospital to hospital and may be regulated by the medical staff. There are various situations that can lead to a gross only description, but in reality there are two main situations where it is considered a gross only: 1. SPECIMENS THAT CANNOT BE PROCESSED Gross only – certain specimens come to the  Foreign bodies such as: lab that will only be  Hardware (screws, pins, plates, bone cement) – orthopedic grossly described and  Bullets & Breast implants => documentation required since cases of reported but not further litigations. processed.  Kidney stones => these are sent out for crystal analysis.  Gallstones  Dense bone => it is very difficult to process.  A tooth => it is very difficult to process. 2. SPECIMEN THAT NORMALLY IS “GROSS ONLY” depending on the institution:  Soft Tissue (e.g. ear cartilage, adipose tissue, optic lenses, placenta from normal deliveries, scar tissue, debridement tissue, tonsil and adenoids, varioceles, vein stripping  These specimens are examined and described. If any of the areas are suspicious, a section is taken for processing. Results are normally available within 24 hours. 2. “Gross and Microscopic”  This process will generate a physical description of the specimen received as well as a report of the microscopic findings. The result reported is obtained from the dictation of paraffin blocks that have been processed with dissected tissue during the gross examination.  A tissue can generate as little as 1 block to as many as needed.  Part of the gross and microscopic finding relies on the Hematoxylin and Eosin (H&E) stain. Generally the turnaround time (TAT) is 24 hours, unless decalcification or special stains are ordered, this will prolong the final report Specimen Procurement – where do specimens come from?

2 Tissue specimens received in the histology laboratory come from a variety of places:  Hospital Operation Room (inpatient and outpatient)  Morgue (autopsy)  External Sources (prepared material sent for additional diagnostic assistance)  Private Doctor's Office  Out patient clinics  Family physicians will occasionally remove a skin lesion for diagnosis Types of Specimen Submitted to the Histology Laboratory Specimens come into the lab either already “fix” and in a container or fresh, unfixed and usually on top of a surgical towel “FIXED TISSUE” -The following are examples of fixed tissue sent to the histology laboratory in the appropriate fixative solution: biopsies, all or part organs, amputations, autopsy  Biopsies - are small sections of different organs removed to determine the presence of pathology possibly affecting more of the organ. Types of biopsies are: o Needle -Threadlike biopsy obtained by inserting a hollow needle through the skin into an internal organ (e.g. breast, prostate, liver) o Excision Biopsy - This usually involves the removal of a small lesion; for instance, a small skin lesion that is totally excised can be classed as an excision biopsy o Endoscopic Biopsy - A small specimen of the digestive or respiratory tract can be obtained by inserting an instrument (endoscope) either by mouth or rectally and a small piece of irregular tissue is obtained (e.g. stomach, colon biopsies) o Abrasion Biopsy - Occasionally a specimen is received that is abraded from the surface of a lesion, e.g. a skin or mouth lesion. This is done using a sponge or brush. o Cone Biopsy - This refers to a special procedure in which a cone-shaped portion of the cervix is removed. o Wedge Resection – a small specimen is obtained during exploratory surgery. The surgeon takes a small pie-shaped piece of a particular organ, e.g. kidney, liver, or breast Part or whole organs o Breast – whole or partial mastectomies, portions of bowels, gallbladder, uterus, ovary, appendix, lymph nodes, etc. Autopsies Autopsy (necropsy) specimens are obtained when a post-mortem examination (PM) is carried out. This involves examination and dissection of the body after death. An autopsy may be performed for several reasons: o In cases of sudden or unexpected death. The autopsy may be necessary to establish the cause of death. (Permission must be obtained from the next of kin.) o To confirm the clinician's diagnosis for the death certificate. o For medical-legal purposes. The autopsy is performed by a coroner where death is due to murder, drowning or unexplained circumstances. In this case, a court order is granted and permission is not needed from the family. o

For research and teaching purposes - to study normal and pathological changes in

3

o

tissues. Autopsy specimens are usually whole or part organs

Other specimens received in the lab Frozen sections – fresh, unfixed tissue directly received from the OR. The tissue is not put in formalin yet but is instead awaiting immediate examination by the pathologist. The specimen is quickly grossed and rapidly frozen. The tissue is specially cut using a “cryostat”, a slide obtained and quickly stained and viewed under the microscope. This is done for rapid diagnosis when the surgeon is confirming the tissue is cancer and that more tissue must be excised from the patient in the OR ---we will talk more about frozen sections later in the semester. Frozen sections are performed to demonstrate:  Diagnosis  Staging of a malignancy  Special staining procedures  Electron Microscopy Cytology specimens o Specimens of loose cells taken during special procedures; usually for cancer investigations The Gross o Specimens in the lab are usually received immersed in fixative in containers. However, under some circumstances specimens are received covered by saline-moistened gauze. For routine histological preparation, the specimen should be transferred into fixative immediately. At no time should the specimen be allowed to dry out. o As a reference to the original appearance of the tissue prior to fixing, a photograph may be taken of the whole organ or part of the specimen. Some special procedures may require an unfixed tissue specimen, e.g. tissue imprints and specimens to be cultured for bacteria. Other procedures, e.g. electron microscopy, require special fixation. o When a specimen is received in the lab, be aware of the size and shape of the specimen container compared to the size of the specimen. Make sure that the tissue can be taken out of the container once the tissue has been fixed; a narrow neck on a bottle, for example, could prevent removal of a fixed tissue specimen.

SPECIMEN IDENTIFICATION - specimen accessioning

4 o

o o

o

The first step in specimen identification is to check the label on the container against the requisition to make sure the labels match. Then assign a lab number to the specimen from the pathology lab information system. This is usually a consecutive numbering system that starts at the beginning of the New Year. The patient's name, the date, the tissue type and the doctor's name are entered into the LIS beside the specimen number from the information on the requisition. The requisition and the container (both side and lid) are labelled with the lab identification number. Surgical specimens are indicated, e.g. S-13 - 1500 If more than one container is received for the same patient, all containers should be given the same surgical number, e.g. uterus and ovaries - S – 13 – 1500 (1)- for the uterus and S-13 – 1500 (2) right ovary, and S -13- 1500 (3) – left ovary. Labs may vary with the placement of the year and the use of letters, according to the system in use.

Description Specimen description is done by a pathologist, a resident in pathology, or a technologist. This description must be clear, concise and accurate. The following points should be noted: o Fixative used o Type of specimen and the surgical procedure o Colour o Consistency (texture) o Dimensions or the volume, in SI (metric) units o Weight (in grams) if it is a whole organ, e.g. lung or kidney o Any abnormalities, e.g. lesions, and their orientation to normal tissue or to surgical margins. Depending on the particular specimen, other descriptive terms may be used. Gloves must be worn when handling specimens. The description is usually dictated. Block section o Before block selection, the number on the requisition and the specimen container should be checked to make sure that they match. Tissue is then selected for further processing. The entire contents of the container, e.g. D&C curettings, may be submitted in one cassette (with no letter designation), or certain areas of a larger specimen in several cassettes (labelled A, B, C, etc., respectively). o A tissue cassette is labeled in pencil or special pen with the specimen number. o The tissue is placed inside the cassette and the lid securely fastened. The cassette is then placed into a tissue basket containing fixative. Later in the day, the baskets of tissue cassettes will be loaded onto the automatic processing machine. If the entire specimen is not submitted for processing, the remainder is put back into the original container with fixative and filed. o As the tissue is grossed, the lab number is entered on the daily worksheet. Any special procedures to be done on the specimen, e.g. special stains or deepers (levels), should be noted on this sheet. o Some specimens received in the lab may or may not be processed, e.g. bone chips, teeth, toenails, or kidney stones. They are given a lab number and then filed.

Blocking a specimen

5

Marking tissue o It is sometimes requested that a particular area (which may be visible only on one side of the tissue block) be presented for microtomy. The tissue must then be marked in some way so that when it is ready for embedding it is properly oriented with the requested area against the base of the mold. Equipment used to gross o Usually done in a well-ventilated room under a fume hood o Many pieces of equipment can be used during gross examination o A cutting board and tray serves as a cutting surface o Forceps, scalpels, ruler, weight scales o Tissue cassettes, specimen jars o Formalin container, formalin o All utensils must be cleaned before each new specimen to prevent contamination o All utensil is sterilized after use...