histology
Meaning of histology: Architecture is the point: how cells sit relative to one another often says more than how any single cell looks.
Definition of histology
Histology is the study of tissue structure at the microscopic level. In hospital use the word also covers the practical process that makes such study possible: fixing, embedding, slicing and staining a sample taken by biopsy or surgery so that its cells and their arrangement can be examined under a microscope.
How histology is built
- hist/o Combining form · Greek tissue
- -logy Suffix · Greek study of, body of knowledge
A medical term is read from its ending backwards: the suffix first, then the prefix, then the root. See all 223 word parts.
How does a specimen become a slide?
Fixation in formalin comes first, halting decay and locking proteins in place. The water in the tissue is then replaced by wax so the sample is firm enough to cut, and a precision blade shaves sections only a few cells thick. The wax is removed and dye applied, most commonly a pair that stains nuclei blue-purple and cytoplasm and connective tissue pink, giving the familiar appearance of a slide. Further techniques answer narrower questions: special stains for organisms, iron or fibers; immunohistochemistry, which uses antibodies to reveal particular proteins and so identify what a cell descends from; and molecular tests run on the same tissue block. A frozen section skips most of this to give an answer during an operation, at some cost in detail.
How does it differ from cytology?
| Histology | Cytology | |
|---|---|---|
| What is examined | A piece of intact tissue | Individual or loosely grouped cells |
| How it is obtained | Biopsy or surgical specimen | A brush, scrape, fine needle aspirate or a sample of fluid |
| What it shows | Cell detail plus the architecture around it, including whether cells have invaded | Cell appearance only |
| Usual role | Definitive diagnosis and staging | Screening and rapid assessment |
That difference matters most for cancer. Whether abnormal cells have broken through the basement membrane beneath them is what separates a contained change from an invasive one, and only intact tissue shows that boundary.
What does the report describe?
It records what was received, what tissue is present, how the cells are arranged, and how far that departs from normal, noting inflammation, infection, scarring or abnormal growth. Where a tumor is found it states the type, the grade, how far it extends, whether it reaches the cut edges of the specimen, and whether it has entered blood or lymphatic vessels. Those items feed directly into staging and into what happens next, which is why a biopsy is so often the step that settles a diagnosis that imaging could only suggest.
Used in a sentence
The biopsy specimen was sent for histology to determine the nature of the mass.
Good to know
Histology examines intact tissue architecture obtained by biopsy, while cytology examines individual or loosely grouped cells, a distinction that affects how each sample is collected and what it can show.
Word origin
Where “histology” comes from
Formed from histo-, from Greek histos, meaning tissue, and -logy, meaning study of.