Pathology, surgical pathology is one of the less kown "behind the scene" medical professions. People rarely meet or hear about the pathologist and most of them only belive that those are guys responsible for human autopsy.
In my opinion it is important to talk about the tasks and challenges of cytology, and (patho)hystology. It is crucial to pay attention for the pitfalls of tissue sapling and the ways to (better) understand pathological reports. My plan is now to give a brief summary of the most important tasks and I'll discuss the details in later posts.
Pathologists are those who give final diagnoses from biopsies, cytologic samples, samples removed during sugical operations. The decision sound very simple (indeed it is sometimes realy challenging)but the responsibility is huge.
"The only problem with this job is that one can never learn it!" - told a famous, highly respected professor of pathology (Pongrác Endes) when he was 86 years old.
Once a tumor is graded as malignant much more radical precedure starts to defeat the tumor or the possible metastases - radical excision, chemo- or radiotherapy, etc. with all the consequences. If the tissue sample is graded harmless then the actions are much indulgent - if mistaken the tumor can spread easier.
All in all, in an optimal case the pathologist is guiding the surgeons hand.
But this story begins days before the surgical slide lands in the microscope! So what are most important steps before the final diagnosis.
Tissue sapmpling
If a sample is unproperly taken or processed sometimes it is realy impossible to give a decent opinion - repeated sampling - if it is possible at all - is another torture and risk for the patient and waste of the time too.
Tissue sample can arrive from surgical operations, biopses (taken with needle or endoscopes, etc), cytologic samples (from female cervix, bronchi, etc). The WHO is giving guidelines and procedure descriptions for surgeons how to take and preprocess the different samples (some should be put in formaline, some in physiological saline, others are put for a short period into ethanol or aceton).
Why I pay this amount of attention for this topic is my bad experience how surgeons don't seem to care the samples taken. Damaged needle biopsies, breast excisions without proper orientation, samples crinked into small boxes...
"The gross room"
When the tissue samples arrive into the pathology departments, it is strickly regulated - small variations can occure from lab to lab - from which part of the sample with which orientation how many tissue blocks should be cut out for embedding and sectioning. In many cases not only the sample itself but also the adjacent lympnodes should be processed (even the number of isolated lymph nodes can be crucial when setting the final diagnosis).
Stainings
As a first step in most of the cases paraffin embedded sections are stained with Haematoxylin and Eosin. In simple cases this staining is enough for the decision. If not then special stainings can be used for demonstrating different tissue components (like Van Gieson, or PTAH).
Nowadays in the differencial diagnosis of the tumors immunhistochemistry is an indispensable further step, when specific proteins, oncogenes, etc. should be identified. The presence or absence of receptors or other molecules can have real substantial role when estimating the prognosis and planning the therapy of a tumor.
Final decision and report
In most of the cases the decision is made by one patholgist, but in complicated cases shorter-longer consultation is necessary. In the past years a new way of consultation the so called telepathology became available in more and more labs with the introduction of Virtual Microscopy.