Histopathology Flashcards
what occurs in the stage of booking in a sample?
specimen taken, labelled ensuring correct identity
what occurs during fixation?
samples sent in formulin or frozen forms to the clinic
in what situations would formulin not be used?
when it would impede studies of proteins such as if immunofluorescence needed or enzyme studies
why does formulin impede studies of proteins?
forms cross-links between proteins which preserves structure but loses function
what is an artefact?
any structure or feature in histological section that is not usually present in tissue
what is the process of dissection?
aim to transfer pieces of tissue into cassettes
what is the dissection process of small transfers?
limited or no amounts of dissection required as it is all tissue processed
what kind of biopsies are small transfers?
core biopsies such as lung or breast, cervical biopsies
what is the dissection process for intermediate specimens?
requires dissection and sampling, some may be represented using small representative section
what are examples of intermediate specimens?
skin cancer excision, gallbladders
what is the dissection required of a large specimen?
needs dissection by a consultant
what is the purpose of processing of a sample?
to remove water and infiltrate with molten paraffin wax
what reagents are used in the processing stage?
alcohol, xylene and molten wax
what is the purpose of the 3 reagents used in processing?
alcohol removes water, xylene replaces the alcohol and the wax replaces the xylene
what is the embedding process?
transferal of the tissue to a wax block
what is important during embedding?
that it is placed in orientation that is best for analysis of abnormalities
what is the microtomy process?
to shave a thin section from the wax block and mount onto a microscope
how thick is the microtomy section?
0.003mm thick
what machine carries out the microtomy stage?
microtome
what is an advantage of embedding?
provides more mechanical strength for cutting
what does haemotoxylin do?
it is a basic dye and so stains acidic areas such as DNA in the nucleus
what does eosin do?
it is an acidic dye and so stains basic areas pink
what is immunohistochemistry?
using specific antibodies to bind to antigens in specific areas of the tissue
what stains are used in a colposcopy?
acetic acid which stains abnormal areas with high DNA content white, and Lugols iodine which stains normal cells brown
what are the 2 layers of epithelial tissue present in breast?
myoepithelial which is contractile and luminal which is secretory
what are the different possibilities of lumps found in the breast?
lipoma, fibroadenoma, carcinoma, phyllodes tumour, cyst or fat necrosis
what is a lipoma?
benign proliferation of adipose cells
what is a fibroadenoma?
benign tumour with epithelial and stromal involvement
what is a phyllodes tumour?
on a spectrum of benign to malignant
what is the histopathology of a breast carcinoma?
lose the myoepithelial layer of tissue
how can histopathology of a breast carcinoma be analysed?
using a p63 antibody to stain the myoepithelial layer of tissue
what 3 sources of information are used in diagnosis?
clinical (C), radiological such as an MRI (M) and pathological results including histology and cytology results (B)
what is category B1?
normal tissue
what is category B2?
benign lesion
what is category B3?
lesion of uncertain malignant potential
what is category B4?
suspicious
what is category B5?
malignant
