The Pathway of a Pathology Specimen for Diagnosis
To request pathologic interpretation of any specimen, it is sent by a surgeon from the operating room or from other physicians’ offices directly to the pathologist. The specimens are transported in special containers with a pathology laboratory requisition form attached; it contains all of the relevant information on the patient, the specimen, and the referring physician.
Each specimen sample is assigned a unique case number in the laboratory computer system called an accession number. This step is the beginning of the specimen processing as well as the identifier for the Pathology Report. First, either a Pathology Assistant (that is, a trained staff technologist) or a pathologist, or both, will examine the specimen and provide a macroscopic or gross description that includes the specimen type, location, size, weight, color, and any other distinguishing characteristics.
The specimens are then placed, entirely or in part, in a formaldehyde solution and prepared with an automatic tissue processing machine. Afterward, a histotechnologist embeds the tissue in paraffin (wax) blocks. It can then be cut into slices with a microtome (a sharp-bladed machine), and stained with various biological dyes. Those samples form the basis for pathologic examination with a microscope. Depending on the specimen type and the complexity of the disease process, several additional stains may be required. Therefore, the number of slides prepared can vary widely. For instance, one colon biopsy may only require three slides for a diagnosis to be made, whereas another similar case may need fifteen.
When the slides have been prepared, they are “read” by a pathologist. Pathology is a field comprising many subspecialty areas, and PRW therefore matches the type of biopsy being evaluated with the pathologists’ special interests and knowledge. PRW pathologists are also teaching physicians, and many cases will be reviewed using a multi-headed microscope so that residents and fellows (pathologists in-training) can study the specimens in conjunction with the supervising pathologist.
After examining the specimen under the microscope, the pathologist dictates a microscopic description of the findings and a final diagnosis section in the report. It is then “transcribed” by medical secretaries and converted into a written document that can be sent to the referring physician by mail, e-mail, internet, or FAX. Although the pathologist will, of course, be available for subsequent consultations, the overall results of the pathology report are generally discussed with patients by their own physicians.
What is the Practice of Pathology?
Physicians who practice as pathologists are frequently described as the “Doctor’s Doctor” because, with some exceptions, they generally interact with a patient’s physicians rather than with the patient directly. The medical specialty of pathology is dedicated to the general study of disease and its processes as well as the specific diagnosis of various disease processes. Those goals are accomplished through the examination of organs, tissues, body fluids, cells, and specific molecules.
The origins of pathology date back to the Italian Renaissance as one of the earliest examples of a scientific approach to medical practice. The word pathos derives its roots from the Greek term for pain and suffering; hence, pathology is the detailed study of causes for that pain and suffering. By the late 19th century autopsy (postmortem) examination had become a major source of medical knowledge, and researchers soon extended their investigations to a microscopic level. Throughout the 20th century, the technological elements of pathology practice grew at a steady pace, incorporating knowledge from other scientific disciplines such as anatomy, histology, biochemistry, and molecular biology.
Because of television and movie presentations, many people think only of autopsies when they hear the word “pathologist.” Although postmortem examinations do remain an important area in the current practice of pathology, they represent only a small part of the work that modern pathologists perform.
PRW pathologists are engaged in clinical work every day. They also participate in the training of pathology residents and fellows, and the education of medical students. Members of the PRW professional staff use an collaborative approach to their work, in which scientists and physicians strive to work in conjunction with each other to integrate the knowledge gained in research with the needs for patient care. That orientation is also known as “translational” medicine because it involves moving between the work of research laboratories and clinical practice. To that end, PRW pathologists have published research papers in scientific journals and several of them have served as invited speakers at national and international pathology meetings.
The Work of Pathologists
In the twenty-first century, pathologists continue to be leaders in the investigation, identification, and understanding of disease. The discipline of anatomic pathology encompasses several subspecialties such as surgical pathology, cytopathology, hematopathology, molecular pathology, cytogenetics, neuropathology, pediatric pathology, and renal pathology.
Anatomic Pathology comprises surgical pathology, cytopathology, and autopsy pathology. Anatomic examinations generally involve both gross (i.e. visible to the eye) and microscopic visual examination of tissues. Those procedures employ biological staining techniques to detect proteins and other molecules of diagnostic interest in tissue specimens using the microscope.
Pathologists are board-certified in Anatomic Pathology (AP) or Clinical Pathology (CP or Laboratory Medicine) or both, by the American Board of Pathology or similar international boards. “Board certification” means that a physician has achieved (and maintains) the standard of practice and competence that is required by a professional specialty board. Subspecialty certification may also be obtained in cytopathology, dermatopathology (pathology of skin disease), forensic pathology (with a focus on the cause and manner of death), neuropathology (pathology of the central nervous system, muscles, & nerves), and pediatric pathology (pathology of diseases seen in children).
Clinical Pathology, or Laboratory Medicine, is the medical subspecialty that concerns the diagnosis of diseases based on the laboratory analysis of various body fluids. Examples include blood, urine, stool, mucosal secretions, and cerebrospinal fluid. Many CP tests are automated, and the clinical pathologist is responsible for overseeing laboratory technologists who perform them. Laboratory Medicine also includes quality assurance and supervision, pathological interpretation of complex studies such as flow cytometry and nucleic acid-based assays, and consultations with clinicians to determine the use of appropriate testing for the diagnosis of particular diseases.
In the area of Clinical Pathology, subspecialty certification may be obtained in blood banking/transfusion medicine (the therapeutic use of blood products), chemical pathology (clinical chemistry), hematopathology (the study of blood components, bone marrow, and lymph nodes), medical microbiology (the study of microorganisms and infectious diseases), and molecular genetic pathology (studies of disease at the level of cellular DNA or RNA).
How to Read a Pathology Report
Your physician will be notified of any abnormal results found by PRW pathologists. In nearly all cases, the contents of your pathology report will be presented to you by your clinician and discussed with you in private. Your doctor will help you understand the details in the report. In general, there are a number of common sections that virtually all pathology reports share and it may be useful for you to know how such information is organized.
Each report begins with confidential demographic patient information (age, sex, home address, birth date, etc.), followed by a detailed list of the specific specimens that were received and a thorough macroscopic (also called “gross”) description of the specimen. A summary is included that indicates which tissue blocks submitted for microscopy correspond to the slides that are ultimately produced. For each specimen, diagnoses are presented in bold font. The particular listing for each diagnosis indicates the precise “site” of the specimen, i.e., its location in the body, the procedure through which that particular specimen was obtained from the site, and the actual pathologic diagnosis, with reference to additional comments if necessary. Among other relevant information, the diagnosis will indicate—implicitly or specifically—whether the identified disease is benign or malignant. The report may also indicate the pathologic stage of malignant diseases, the level of differentiation of tumors, and other information that can be used to plan subsequent therapy. The signature(s) at the end of the document, which are usually inserted electronically, attest that the final diagnosis has been personally formulated by the reporting pathologist(s)
Sometimes an addendum report is required. That communication usually contains results of additional studies that were performed after the initial diagnosis was made. If diagnostically-important information comes to attention well after the report is issued, the pathologist may choose to make an amended report to reflect those facts.