Before examining the tissue with a microscope, the Histology technician prepares a slide. During this process, the specimen is cut into thin slices, called histologic sections. They are then stained with various dyes, which show the parts of the cells. The Histology technician places the sections on a glass slide. Next, they place a thin cover called a cover slip on top to hold the specimen in place. The pathologist will then look at the sections under a microscope.
Here are the types of slides your technician may prepare:
Permanent section:
To create a permanent section, the technician places the specimen in a fixative for several hours. A fixative is a substance that keeps the specimen “fixed” so that it does not change. The length of time the specimen stays in the fixative depends on its size. Formalin is the fixative used most often. It causes the proteins in the cells to become hard so that they do not change.
Then the technician places the fixed specimen in a machine. This machine removes water from the tissue and replaces it with paraffin wax. Afterward, the technician embeds the specimen in a larger block of paraffin. Paraffin blocks are durable and can be stored indefinitely. Once the paraffin block hardens, a technician cuts the specimen into extremely thin slices using a machine called a microtome. The thin slices are then floated in water so that they can be scooped up onto the slide.
After the slice is on the slide, the paraffin is dissolved from the tissue and water is added back. Then, a technician uses dyes to stain parts of the cell. The center of a cell, called the nucleus, is where genes are found. This is stained a dark blue. The contents of a cell between the nucleus and the cell membrane is called the cytoplasm. This is stained pink or orange.
Smear:
If the specimen is a liquid or if small pieces of tissue are in a liquid, a slide is prepared differently. The doctor smears the specimen on a microscope slide and lets it air dry. Then, a fixative is sprayed on it or places it in liquid or let it dry to fix it. The fixed cells are then stained and viewed under a microscope.
What is the diagnosis?
A. Chordoma
B. Ecchordosis Physalifora (Notochordal rest)
C. Benign notochordal cell tumor
D. Thornwaldt cyst
Benign Notochordal Cell Tumor
Clinical: Benign intraosseous, slow-growing neoplasm derived from notochordal
remnants, usually located within the axial skeleton; thought to be precursor lesion of
chordoma
Imaging: May show up as a solitary, sclerotic area confined to the vertebral body;
occasionally multiple
Histology: Sheets of large polyhedral cells with abundant clear to pale pink cytoplasm,
well-defined cytoplasmic membranes, occasionally with intracytoplasmic hyaline
globules, and round mildly pleomorphic nuclei. No myxoid stroma present (important
for distinguishing BNCT from chordoma).
Ancillary studies: Keratin+, EMA+, S100+, brachyury+
These are world wide Histotecnology associations :-
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