Pathology: more than autopsies

Sometimes when I meet new people and tell them what I do, their first question is something like “So you do autopsies on dead people?”  My thirty second elevator pitch must need some work because their eyes usually glare over and they politely excuse themselves when I explain that, unless you work for a medical school or Coroner’s/ME Office, autopsies are a small part of the job.  It’s a shame that most of the public’s only experience with pathology is the unrealistic dramatizations observed in movies or television.  There are a large number of health care workers that also don’t understand that pathologists do so much more.

The majority of pathologists practice in a hospital or clinic setting and specialize in anatomic (surgical) or clinical pathology.

Anatomic Pathology

Anatomic pathology involves the gross and microscopic (histologic) examination of tissue to diagnose disease.  When you go to the clinic and have a suspicious mole scrapped, or a have a polyp removed during colonoscopy, or have a needle core of a breast lump or enlarged prostate; those samples are sent to an anatomic pathologist for evaluation.  Anatomic pathology is also where tissue removed during surgery is evaluated to diagnose disease and act as a quality control measure.

Generally speaking, the tissues are checked in by a technician and assigned a tracking number (accessioned).  The tissue is then examined and described by a pathologist or a certified pathologist assistant (PA), called the gross examination.  Details such as the dimensions, weight, color, texture, and even sometimes smell are recorded.  Biopsies and smaller samples are placed fully (in toto) into a tissue cassette then soaked in fixative such as 10% formalin (a formaldehyde solution).  For more complex surgical specimens, it is important that samples be taken in a specific way and from specific areas to accurately diagnose and stage the case. Quarter-sized samples are placed into cassettes and allowed to soak in formalin until placed into a tissue processor.

Certified histotechnologists (HT/HTL, ASCP) embed the processed tissues into paraffin then use a microtome to cut very thin sections that are mounted to glass slides.  The glass slides are then stained and cover-slipped.  The pathologist examines the shape and color of cells present on each slide to determine a diagnosis that is reported back to the patient’s clinician. Accurate staging and grading of disease is vital for directing appropriate treatment by clinicians.  TNM Staging is done using the American Joint Committee on Cancer‘s standardized criteria, facilitating communication among teams with multiple specialists.

Clinical Pathology

Clinical pathologists generally oversee laboratory functions or departments such as clinical lab, microbiology, and blood banking.  The clinical lab is where blood and body fluids are sent for testing.  Many of today’s chemistry tests are run on a machine by certified Medical Technologists (MT, ASCP) that then review the machine’s findings and double check any abnormal reports.  Some tests such as cell counts may be performed by evaluation of the sample under a microscope.

In microbiology a sample is streaked onto a plate of gel that encourages pathogens to grow.  The pathogens grow into colonies that can be sampled and evaluated microscopically, chemically, or at a molecular level to determine the exact pathogen.  The name and sub-type of the pathogen is important to physicians treating patients; ensuring that the treatment is effective while being the least harmful.

Blood bank is exactly what is seems; it’s where blood is stored for transfusion.  Personnel do more than act as an inventory or supply function, they ensure that blood given to patients is safe and least likely to cause a reaction.  This done through processes called typing, screening, and cross-matching.

Finally, clinical pathologists perform similar functions to that of anatomic pathologists in that they examine tissues involved with blood and bone marrow diseases such as myeloma, anemia, sickle cell, and lymphoma.

Although patients rarely have direct contact with a pathologist, in both cases, anatomic and clinical, pathologists play a vital role on the patient care team.  Today’s treatments are becoming more specialized and targeted.  The appropriate diagnosis and staging of diseases by pathologists ensures that patients get the best care possible for their specific condition.


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