PATHOLOGY: A CAREER IN MEDICINE – 2018 EDITION
The Scientific Foundation for Medical Practice
Pathology is the medical specialty that provides a scientific foundation for medical practice
The pathologist is a physician who specializes in the diagnosis and management of human disease by laboratory methods. Pathologists function in three broad areas: as diagnosticians, as teachers, and as investigators. Fundamental to the discipline of pathology is the need to integrate clinical information with physiological, biochemical and molecular laboratory studies, together with observations of tissue alterations. Pathologists in hospital and clinical laboratories practice as consultant physicians, developing and applying knowledge of tissue and laboratory analyses to assist in the diagnosis and treatment of individual patients. As teachers, they impart this knowledge of disease to their medical colleagues, to medical students, and to trainees at all levels. As scientists, they use the tools of laboratory science in clinical studies, disease models, and other experimental systems, to advance the understanding and treatment of disease.
Pathology is the medical specialty that provides a scientific foundation for medical practice
The pathologist is a physician who specializes in the diagnosis and management of human disease by laboratory methods. Pathologists function in three broad areas: as diagnosticians, as teachers, and as investigators. Fundamental to the discipline of pathology is the need to integrate clinical information with morphologic, physiologic, biochemical, and molecular laboratory studies. Pathologists in hospital-based and other clinical laboratories practice as consultant physicians, developing and applying knowledge of tissue and laboratory analyses to assist in the diagnosis, treatment, and long-term management of individual patients, and in prevention of and screening for disease in the population. As teachers, they impart this knowledge of disease to their medical colleagues, to medical students, and to trainees at all levels. As scientists, they use the tools of laboratory science in clinical studies, disease models, and other experimental systems, to advance the understanding and treatment of disease.
Pathology has a special appeal to those who enjoy solving disease-related problems, using technologies based upon fundamental sciences ranging from biophysics to informatics to molecular genetics, as well as tools from the more traditional disciplines of anatomy, biochemistry, pharmacology, physiology and microbiology.
The Pathologist in Patient Care
The pathologist uses diagnostic and screening tests to identify and interpret the changes that characterize different diseases in the cells, tissues, and fluids of the body. Anatomic pathology involves the analysis of the gross and microscopic structural changes and associated biochemical and genetic abnormalities caused by disease in tissues and cells removed during biopsy and aspiration procedures, in surgery, or at autopsy. Clinical pathology encompasses chemistry, hematology, coagulation, transfusion medicine/blood banking, microbiology, and immunology, among other types of laboratory modalities. Molecular pathology utilizes strategies for DNA and RNA sequencing, hybridization, and/or amplification, as well as proteomics, to aid in many aspects of both clinical and anatomic diagnoses and patient management. Collectively, all the pathology specialties contribute to understanding disease and diagnosis and treatment of the patient.
For all pathologists – clinical, anatomic, molecular, or researcher – better patient care is the ultimate goal. Pathologists participate in day-to-day care of patients by providing and interpreting laboratory information to help solve diagnostic problems and to monitor the effects of therapy. Because of the expanding volume of new and highly complex tests, other physicians rely on the pathologist for guidance and direction in use of the clinical laboratory and interpretation of test results. The rapidly evolving field of molecular diagnostics is driving precision medicine initiatives and involves techniques that permit detection of carriers of genetic disease, identification of genomic abnormalities that determine the treatment and prognosis of neoplasms, determination of genomic patterns that predict response to medications (pharmacogenomics), rapid diagnosis of viral and bacterial infections, and DNA fingerprinting for forensic (medico-legal) analysis. When unusual or unexpected abnormal results are identified, and particularly when critical or life-threatening alterations are found, the pathologist communicates directly with the patient’s physician.
The newly evolving field of computational pathology applies quantitative analytics to the data obtained from molecular, cellular and tissue imaging, and multivariable clinical laboratory tests. Machine vision, machine learning, artificial intelligence and the human intelligence-machine intelligence partnership are the subject matter in computational pathology.
In addition to daily communication with other health care professionals about test results, many pathologists have direct patient contact on a frequent, and even daily, basis. It is common for the pathologist to perform a fine-needle aspiration of suspicious masses or a bone marrow aspiration or biopsy to diagnose hematologic disease. One of the most direct patient management and practice roles that some pathologists perform is apheresis therapy, a process that removes pathologic substances from the blood stream in a variety of disorders and can be immediately life-saving or used for long-term care. A relatively new way that pathologists interact with patients is through direct communication with patients regarding a recent diagnosis of cancer and the implications for treatment and prognosis. In these ways, pathologists not only provide acute care, but also form long-term relationships with patients and their families.
Whenever tissue is removed from the body, it must be examined to determine the precise cause of the illness that prompted its removal. Gross and microscopic analysis of tissue changes is the primary focus of anatomic pathology, aided by correlation with ancillary studies such as immunohistochemical, molecular genetic, and flow cytometric analysis. Within the practice of anatomic pathology are subspecialty areas including surgical pathology, neuropathology, cytopathology, autopsy pathology, and forensic pathology. Pathologists in community hospitals often practice in most of these subspecialty areas. Pathologists in academic medical centers usually subspecialize in only one area, and sometimes in a specific organ system
The surgical pathologist plays a central role in the diagnosis of biopsies or of surgically removed tissues, particularly when a neoplasm is suspected, and works closely with surgeons, oncologists, and other physicians in such cases. Endoscopic and other minimally invasive methods are often used to examine the airways, gastrointestinal tract, and deep-seated lesions. Biopsies performed during such procedures may produce very small samples of tissue, but the pathologist is typically able to perform detailed analysis and determine the specific medical disease or neoplastic diagnosis.
Surgical removal of malignant neoplasms often results in complex specimens that require intricate examination by the pathologist. The surgical pathologist is trained to identify evidence of disease at the macroscopic and microscopic level. Knowledge of typical gross abnormalities and an understanding of the information that is important for patient management (such as the status of resection margins) guides the pathologist in selecting tissue samples for examination under the microscope.
Often during surgery for suspected cancer, a pathologist is asked to provide intraoperative consultation to the surgeon. A portion of tissue removed during the operation is subjected to frozen section and/or imprint microscopic examination and a rapid diagnosis is determined by the pathologist while the patient is still on the operating table. This preliminary diagnosis guides the surgeon as to the next steps to take during surgery.
Complete pathologic work-up of tissue specimens increasingly requires correlation of histologic findings with the results of immunohistochemical, flow cytometric, and/or molecular analyses. In many cases, DNA sequencing and other molecular studies are essential not only in classifying neoplasms but also in determining prognosis and guiding selection of therapy directed to specific molecular targets. Surgical pathologists are crossing over into the realm of digital pathology. The high resolution cellular and tissue images which they use are rapidly becoming substrate for quantitative image analysis and computational pathology approaches.
The cytopathologist is specially trained to examine and interpret the microscopic appearance of cells shed into fluids such as urine or body cavity effusions, scraped from the uterine cervix, or aspirated from tumors with a fine needle. Cytopathologists often perform the fine-needle aspiration procedure themselves, especially when the tumor is palpable, and increasingly use ultrasound guidance during the procedure. In other situations, the cytopathologist interprets cells obtained by aspiration of deep-seated lesions (e.g., in the lung, mediastinum, retroperitoneum, or other sites) performed by another physician such as an interventional radiologist. Special studies, including immunohistochemical stains and molecular analyses, are performed on cytologic specimens in many cases to better refine the diagnosis and guide therapy. Quantitative image analytics of cytopathology supports computerized decision support for cytopathologists.
Autopsy pathology is part of the foundational education of pathology residents and is practiced by some, but not all, pathologists. The autopsy provides unique insights into the natural history of disease and the influence of therapy on disease processes. Although autopsy information is important for general medical purposes, occasionally the patient’s family is benefited directly. For example, when an unsuspected genetic disorder is found or evidence of a contagious infection or an environmental toxin is uncovered, the diagnosis and resulting intervention can help living members of that family. The autopsy provides feedback to the physicians involved in patient care about the accuracy of their evaluations and the effectiveness of their treatments. Together, clinicians and pathologists assess the findings in each case so that future patients can benefit from this information. Autopsy data are an important measure of overall clinical quality. Recent studies have shown up to 30 percent discrepancy rates between clinical diagnoses and actual findings at autopsy.
The autopsy is of primary importance in the practice of forensic pathology. The autopsy’s value is often dramatically demonstrated to the public when a pathologist is called upon to determine the exact cause and manner of death in medico-legal cases. Special training and certification in forensic pathology prepares a pathologist to serve as Medical Examiner for a city or state agency, and to conduct laboratory and/or postmortem studies of suspected criminal activities on suspicious deaths or those of concern to public health and safety.
The clinical pathology specialty laboratories include hematology, microbiology, immunology, clinical chemistry (including toxicology), and the blood bank (transfusion medicine). In these areas, the pathologist acts as an important consultant to the clinician, recommending appropriate tests and interpreting their results. The pathologist also plays a key leadership role in ensuring that the laboratory provides cutting-edge testing of the highest possible quality.
In hematopathology, for example, pathologists oversee hematologic testing in the laboratory and provide interpretation of abnormal blood smears and other tests, such as hemoglobin electrophoresis and special coagulation tests. The pathologist also examines and interprets bone marrow aspirates and core biopsies and provides the primary diagnosis in cases of anemia, leukemia, and a wide variety of other hematologic diseases. Another area of hematopathology, which overlaps somewhat with surgical pathology, is in the diagnosis of lymphomas and other complex hematologic disorders involving lymph nodes, spleen, and other sites. In all of these areas, the pathologist interprets the morphologic findings and incorporates the results of special ancillary tests, such as immunohistochemistry, flow cytometry, and molecular analyses, to arrive at a final diagnosis.
In most hospital settings, the pathologist is in charge of the blood bank and functions as a transfusion medicine specialist, directing the procurement, processing, and administration of blood and blood products, selection of appropriate blood products for transfusion to individual patients, and management of transfusion reactions. In this role, the pathologist is key in monitoring and managing the use of blood products in the hospital, serving as a consultant to plan appropriate transfusion therapy, and often overseeing determination of tissue compatibility that permits bone marrow and other transplants.
In clinical chemistry, the pathologist oversees the performance of tests to determine the concentration of organic and inorganic substances and medications in body fluids. Supervision of the use of sophisticated instruments and maintenance of a strict system of quality control and quality assurance are essential to ensure accurate laboratory determinations. The pathologist also interprets certain chemical analyses, such as serum, urine, and cerebrospinal fluid protein electrophoresis, important in the diagnosis of multiple myeloma, immunodeficiency, and neurologic disorders such as multiple sclerosis. Toxicology is often part of the clinical chemistry service, involving the pathologist in therapeutic drug monitoring and detection of illicit drugs and poisons.
In the microbiology laboratory, the pathologist is intimately involved in the detection and identification of infectious microorganisms and in recommending appropriate therapy to treat infectious disorders. Using traditional culturing techniques and increasingly molecular and proteomic analyses, the microbiology laboratory identifies the source of infection and the most effective antibiotics to treat the patient. These analyses are performed as rapidly as possible, and with modern technology, can now be accomplished in hours or even minutes. The pathologist often examines routine and special stains to identify certain microorganisms, such as Mycobacterium tuberculosis, Pneumocystis jiroveci, malarial species, parasites, and other infectious agents.
Testing for immune reactions and allergies is an important area of laboratory activity. Allergic and toxic reactions to foreign materials have long been recognized, but many recently identified diseases reflect immune responses to normal body proteins that are either altered or present in abnormal locations. Immune functions are also critical in toleration of transplanted tissues or organs. Pathologists oversee immune testing in the laboratory and recommend appropriate tests in these often complex disorders.
An important aspect of laboratory practice in both clinical pathology and anatomic pathology is maintenance of high standards of quality and patient safety in laboratory analysis. It is the responsibility of the pathologist to oversee the quality control and quality assurance procedures that contribute to the production of accurate and timely laboratory test results and correct diagnoses. In addition, pathologists constantly seek to offer the most up-to-date analytical technologies and effective testing strategies to support the constantly evolving clinical approach to diagnosis and treatment.
The tools of molecular biology have contributed to the development of many new laboratory testing strategies leading to ever increasing accuracy, precision, and rapidity in the diagnosis of genomic aberrations. Pathologists have been at the forefront of this development and now oversee molecular laboratory operations and participate in the interpretation of many molecular assays. Molecular testing, involving analysis of DNA and/or RNA, is used in most areas of anatomic pathology and the clinical laboratory and involves the application of a growing number of analytical methodologies. Examples include DNA/RNA amplification methods, such as polymerase chain reaction (PCR), in-situ hybridization testing (e.g. FISH), and DNA sequence analysis. Many tests are now part of the molecular pathology laboratory menu including the so-called “next-generation” sequencing (NGS). This technology is revolutionizing the evaluation and management of both somatic diseases such as malignant neoplasms and congenital diseases including cardiac and psychiatric conditions, as well as inherited predisposition to cancer. In addition, infectious agents are now rapidly identified by virtue of their unique DNA and RNA sequences and the new field of pharmacogenomics, which focuses on the genetic basis of the metabolism of many important medications, is affecting decisions on drug selection and dosage. With the growing importance of molecular genetic testing across all aspects of medicine, many pathologists can subspecialize in molecular genetic pathology and become leaders in overseeing and interpreting cutting-edge tests.
Pathology and Clinical Informatics
It is said that 70% of all of the information used to make decisions dealing with clinical care comes from laboratory and pathology data. Lab test results and pathologic evaluations generate large amounts of information and pathologists turn that information into knowledge that is used in the service of their patients. Pathology informatics is the area of pathology practice focused on the collection and management of laboratory information and its synthesis into actionable clinical knowledge. Informatics is embedded in every part of the clinical laboratory and all pathologists are involved to various extents in information management and the use of information technology in their daily practice. Some pathologists take a special interest in informatics and, as pathology “informaticists”, work intensively with laboratory information systems and electronic health record systems, high density molecular data, cellular image analytics, prognostic and predictive modeling functions, and clinical decision support systems. Pathologists and other physicians can now pursue fellowship training and subspecialty certification in a new area of medical practice called clinical informatics. Certification in Clinical Informatics is a joint function of the American Board of Pathology, the American Board of Preventive Medicine, and 7 other collaborating boards.
The Pathologist as a Consultant
The pathologist has long been considered the “doctor’s doctor,” consulted by fellow physicians for selection of diagnostic tests, interpretation of laboratory results, and determination of diagnoses on biopsies, surgical resections, and other specimens. In this role, the pathologist is often at the center of the clinical care team, helping to confirm diagnoses and advising on the treatment and long-term management of the patient. More recently, because of the range and complexity of clinical laboratory services, a role has emerged for the pathologist in explaining laboratory tests and their results directly to patients. In addition, a very different role has emerged for pathologists in this era of value-based health care delivery. Pathologists have considerable experience with laboratory and hospital management and are accustomed to thinking diagnostically across a broad spectrum of human disease. Their familiarity with the principles of quality control, quality assurance, and test utilization management make pathologists valuable assets for the success of accountable care organizations (ACOs) and other value-based health care delivery models.
The Pathologist as a Teacher
Pathologists teach at the bedside, in the laboratory, over the microscope, and in the lecture hall. They instruct medical students, residents in pathology and other clinical training programs, graduate students in basic science departments, and students in related medical disciplines. They are also important in the continuing medical education of practicing physicians in both academic and community settings. The community-based and clinically-intensive academic pathologist has a unique perspective on patients from the viewpoint of each individual’s cumulative laboratory data. This perspective is necessary for consultation on individual patients as well as for guidance on the applicability, interpretation, and usefulness of both standard and specialized, often newly available tests. In the academic setting, the pathologist may be the developer of new testing approaches, responding to evolving patient diagnostic or therapeutic problems. In all these environments, pathologists contribute substantially to teaching on the various clinical services.
Pathology is a required component of the medical school curriculum and is often the first introduction to human disease processes. Additional electives, tutorials, and guided research programs are available to medical students in most schools. Exceptional students may be recognized by the Pathology Honor Society, sponsored by the Intersociety Council for Pathology Information in collaboration with the Association of Pathology Chairs.
To teach well, one must continue to learn. Pathologists are committed to their own educational growth and regularly attend and contribute to programs at local, regional, national, and international meetings, where new basic science findings, diagnostic applications, and technologies are presented.
One of the great appeals of a career in pathology is that it offers the opportunity to teach at many levels. No other medical specialty offers as many different opportunities in education.
The Pathologist in Research
The pathologist-investigator seeks new understanding of the basic nature of disease as a first step toward devising better ways to identify, control and prevent it. In many cases, the normal must be understood in order to define the abnormal. Pathologists have a unique advantage in biomedical research because of their close ties to clinical medicine, their familiarity with laboratory technology, and their recognition of and insight into the significance of diseased tissue changes. Pathologists engaged in research use the sophisticated technologies of modern molecular biology, biochemistry, immunology, cell biology, and tissue pathology. These tools and methods include cell culture, biochemical analysis, electron microscopy, immunologic and molecular genetic techniques, computer modeling, and use of animal models. Understanding at the molecular level is particularly critical in defining normal biological mechanisms, so that the defects that lead to disease can be recognized.
Pathologists are uniquely prepared to investigate the causes and mechanisms of disease because of their experience in recognition of disease manifestations. Examples of the range of problems that can be studied include tracing a newly recognized disease to its origin, improving diagnostic approaches to well-known diseases, and identifying the genetic basis for response (or failure of response) to treatment.
As examples, pathologists have figured prominently in recognition of pulmonary disease among smokers, miners, asbestos and textile workers; of liver cancer from prolonged contact with vinyl chloride and aflatoxin; and of nerve disorders and sterility from exposure to certain pesticides and toxic wastes.
The pathologist plays a key role in improving diagnoses through identification of new pathogenic bacteria, discovery of new infectious agents such as Hanta virus, and better application of modern methods of diagnosis. Some important examples include the unraveling of the role of retroviruses in AIDS, the application of DNA hybridization for rapid and precise identification of atypical forms of mycobacteria that cause infections closely related to tuberculosis, and the identification of the virus that causes SARS.
Pathologists have identified genes that are amplified or otherwise modified in malignant neoplasms and devised methods to test for these genetic abnormalities. These discoveries have contributed to increasingly precise diagnoses and allowed the development of effective therapies targeting specific genetic abnormalities.
Other important pathology research led to the recognition that smoking and obesity are associated with the early onset of atherosclerosis in young Americans as well as the relationship between elevated levels of homocysteine and heart disease.
Pathologists who used their understanding of pathologic processes to make significant contributions to medicine have garnered several Nobel Prizes. Nobel Laureate pathologists include: Alexis Carrel (1912), who pioneered vascular suturing techniques; Karl Landsteiner (1930), the discoverer of the A, B, O blood groups; George Whipple (1934), who, with Minot and Murphy, recognized that liver contained a substance necessary to prevent pernicious anemia; Edward C. Kendall (1950), who, with Reichstein and Hench, studied the hormones of the adrenal cortex, their structure and biological effects which helped develop cortisone as a therapeutic agent; Thomas Weller (1954), who developed methods for the growth of polio virus in tissue culture; Peyton Rous (1966), the discoverer of tumor-inducing viruses; Baruj Benacerraf (1980), who identified genetically determined structures on the cell surface that regulate immunological reactions; Peter C. Doherty and Rolf M. Zinkernagel (1996), who discovered cell mediated immune defense; J. Robin Warren (2005), who with Barry J. Marshall, recognized that gastritis and gastric cancer are caused by infection with Helicobacter pylori; and, Harald zur Hausen (2008), for his discovery that human papilloma viruses cause cervical cancer.
Career Options for Pathologists
A career in pathology offers many options and practice paths. Clinical practice of pathology is typically done in one of two major settings: community hospitals and academic medical centers. Practice in a community hospital setting is the more common model and usually involves combined practice of both anatomic and clinical pathology as a generalist. Community hospital-based pathologists practice in pathology groups of varying size and may provide their services in one or multiple hospitals. In academic medical centers, faculty pathologists who provide clinical services are usually specialists or subspecialists and typically confine their practice to their special area of interest. Clinically-intensive academic pathologists are the most common type of academic pathologist and focus their work mostly on clinical service and teaching, with their research tending to be clinical or translational in nature. Other clinical practice tracks for pathologists include working in a non-hospital-affiliated independent laboratory or commercial reference laboratory.
Another important model for academic pathologists is as a basic researcher. Basic research-intensive academic pathologists typically devote most of their professional effort to performing basic investigation, combined with teaching often focused on graduate students. These pathologists may also provide very limited clinical services, including autopsy pathology, molecular pathology, or subspecialty diagnostic services.
Pathologists who specialize in forensic pathology are usually employed by the city or state government and often serve as Medical Examiners for the jurisdiction in which they serve. Pathologists may serve in other government settings, such as in one of the military branches, the Veterans Administration, the National Institutes of Health (NIH), public health laboratories, or regulatory agencies such as the Food and Drug Administration (FDA).
Pathology training is also an excellent preparation for work in industry. Pathologists may serve as investigators, consultants, or clinical liaisons in companies involved in the development of diagnostic tests, pharmaceuticals, or other biomedical products and services.
The latest available data indicate a continuing strong need for pathologists in all practice settings and employment sectors into the foreseeable future.
Graduate Medical Education in Pathology
Medical school graduates in the United States and Canada need three to four years of accredited residency training to prepare for a career in pathology. There are accredited training programs in many hospitals throughout the United States and Canada, most part of or affiliated with university-based medical centers. There are also many varied opportunities for fellowship training and subspecialty study after residency.
Most pathology residents receive training in both anatomic pathology (AP) and clinical pathology (CP), although it is possible to train in only one. Specialty certification for the medical practice of pathology is the responsibility of the American Board of Pathology (ABP) in the United States, which offers primary specialty (AP and CP) and subspecialty examinations for certification. Four full years of approved training are required for AP/CP, and three years for AP or CP alone. A physician-scientist track (involving additional training) is also available for those residents interested in concentrating on basic biomedical research. Residency training in Canada is the responsibility of the Royal College of Physicians and Surgeons.
Following residency training, candidates requesting certification must pass an objective written and practical examination. As in other medical disciplines, board certification is not required for practice, but it is highly prized as evidence of professional competence. In both the United States and Canada, pathologists who have been board certified must continue to demonstrate competency throughout their careers, and in the United States (except for those who were certified before 2006) must enter the Maintenance of Certification program of the American Board of Pathology.
Pathologists can be certified to practice in the following subspecialties in the United States:
- Blood banking/transfusion medicine
- Chemical pathology
- Clinical informatics (in collaboration with the American Board of Preventive Medicine)
- Dermatopathology (in collaboration with the American Board of Dermatology)
- Forensic pathology
- Medical microbiology
- Molecular genetic pathology (in collaboration with the American Board of Medical Genetics)
- Pediatric pathology
- What is the job outlook for pathologists?
- What are specific Job opportunities? AP (including Cytopath and surgical path subspecialties), CP, integrative molecular medicine, lab management, health systems analytics regarding population health as determined from lab data, informatics, teaching, research, etc.
- What are the evolving opportunities for direct patient contact?
- What is current compensation by specialty and geographic region, academic vs private practice?
- What is the length of training, board certification, maintenance of certification requirements?
- Are there regional/geographic factors that influence type of practice and job opportunities?
- How has the recent expansion of commercial labs affected jobs?
- Are there emerging technologies or interdisciplinary approaches that will generate new types of pathology jobs that are not currently available?
Sources of Information
Contact with pathologists in hospitals, independent laboratories, academic medical centers, and other settings is the best way to learn about the profession and its personal rewards. For additional information about pathology as a career, contact local, state or national pathology organizations, including the:
American Society for Clinical Pathology (ASCP)
American Society for Investigative Pathology (ASIP)
Association of Pathology Chairs (APC)
College of American Pathologists (CAP)
United States and Canadian Academy of Pathology (USCAP)
ICPI is a consortium of five pathology societies (APC, ASCP, ASIP, CAP, and USCAP) created specifically to promote pathology as a career through its publications and information activities. Their website is www.pathologytraining.org.
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