Surgical Pathology – Part 1- Histopathology, Biopsies
- Surgical pathology samples can be obtained from any part the of body e.g.
- Palpable lumps like:
- lymph nodes.
- Soft tissue masses.
- Palpable lumps like:
- From any visceral organs like:
- Intestinal Tract.
- Abdominal cavity.
- Chorionic villus.
- Prostate (transrectal biopsy).
- Head and neck.
- Superficial tissues like :
- Oral cavity.
- Nose and ear.
- The main purpose of the surgical pathology is to diagnose the diseases:
- Inflammatory lesion.
- The biopsy is needed for the differential diagnosis of the lesion.
- The surgical biopsy is needed to see the resection border for tumor infiltrate.
- A biopsy may be done in the follow up of the tumors.
- Surgical pathology may be needed in the recurrence of the tumor.
- Surgical pathology helps in the staging and grading of the malignancies.
- These surgical biopsies are:
Types of surgical biopsies:
- Incisional biopsy when a piece of the tumor is taken for the diagnosis.
- An excisional biopsy removes the whole tumor and submitted for surgical pathology reports for diagnosis and resected margins.
- Punch biopsy when the cervix is biopsied.
- A needle biopsy may with a wide bore needle for bone marrow sampling.
- Fine needle when the bore of the needle is 23 to 25 gauge.
- Curettage biopsy when the endometrium biopsy is taken.
Surgical pathology may be carried as:
- Paraffin section (paraffin-embedded method).
- A frozen section (the tissue is frozen and sectioned). This is a rapid method and available during the surgical operation.
The complication of the biopsy:
- There are chances of bleeding in the case of vascular lesions and liver.
- There is the possibility of the transplantation of the tumor and this may be seen in the scar area.
- There are chances of the dissemination of the malignant cells.
- There may be perforation during the endoscopic biopsies.
- There are chances for the fistula formation in the case of the pancreas and salivary gland.
How to send the specimens:
- The biopsy material should be in the 10 % formalin which will prevent the autolysis of the tissue. Usually, this is buffered formalin.
- Bouin’s solution.
- Carney’s solution.
- There should be 50% times the biopsy volume.
- Never send the specimen in saline or water.
- If formalin is not available then the simple spirit can be used to avoid autolysis. This is advised only in remote areas and when no other choice. Particularly in the underdeveloped countries.
Steps in the processing of the Biopsy:
- Fixation: The biopsy specimen is kept in formalin for at least 12 to 24 hours. This step is very important, If the tissues are not fixed properly then you will not get good slides for interpretation.
- Dehydration: The specimen is put into alcohol or acetone in various grades or concentration. This will remove the water and is replaced by alcohol. This step takes at least 4 to 6 hours.
- Clearing: The specimens are put into xylene which will replace the alcohol and take its place. Now the tissue is fit for the embedding. This process needs 1 to 2 hours.
- Embedding: The specimens are put into melted paraffin (58 °C) and kept there at least for 2 to 4 hours.
- Block making: Then the biopsies are taken from the paraffin and paraffin blocks are made.
- Cutting: The blocks are cut by the microtome with a thickness of 4 to 7 microns. The cut sections are put on the slides.
- Staining: Stain the slides with hematoxylin and eosin.
- Mounting: The stained slides are mounted with the cover glass.
Now the surgical pathologist can read the slides and give his final diagnosis.
- This will takes at least 24 hours for the processing of the biopsy.