L7: Histological Interpretation Flashcards
What are the first three things to take into consideration when interpreting a slide?
Correct specimen, correct clinical forms and details?
What type of tissue sample?
Orientation
What dimension is a histological slide?
Two dimensional cross section of a three dimensional structure
What are the basic principles to consider?
Low magnification important first
Know what structures your stain stains
Histological or cytological preparation
Why is it important to use a low magnification first?
High power–> too much detail–> can make you think you are looking at something really bad
Lower power–> get bearing
What happens to the exudate after inflammation?
Exudate –> lymphatics –> lymph node –> venous system
Upper right portion of body–> right lymphatic duct–> right subclavian vein
Rest of body–> thoracic duct–> left subclavian vein
What are two common states that abnormal tissue can be in?
Inflammed
Neoplastic (new abnormal growth of tissue)
What two states can neoplastic tissue be in?
Benign or malignant
What are the difference between benign and malignant cells?
Benign–> Localise, no invasion beyond BM, no metastases, slow growth, good differentiation, few mitoses, normal cellular chromatin, uniform cell size, compress tissue
Malignant–> Spread, invasion, metastases, rapid growth, poor differentiation, loads mitoses, include nuclear chromatin, pleomorphism (C/N–> bigger nuclei), invade and destroy tissue
What are the two types of malignant tumours?
Primary–> originating from that tissue
Secondary–> spread from primary tumour elsewhere, to new location
Draw a flow diagram to summarise interpreting histology specimen? e.g. lung
Is this lung tissue? Yes: Is this normal? No: Is it inflammatory or neoplastic? Neoplastic: Is it benign or malignant? Malignant: Is it primary or secondary?
What does H&E stand for? Which colour stains which component?
Heamatoxylin–> purple/blue –> nuclei
Eosin–> pink –> cytoplasm and collagen
What are the difference between histology and cytology?
Histology–> cells are in tissue–> biopsy, cancer resection specimens, excised skin lesions, endoscopic biopsy
- Therapeutic as well as diagnostic
- Assess cell architecture as well as cellular atypia
- Differentiate invasive from insitu
- Provide information on completness of exision and info on grading and staging
- Better for immunohistochemical and molecular testing
Cytology–> fine needle aspiration of organs, free cells
- Faster and cheaper
- Non-invasive or minimally invasive and safe
- Cells in fluids
- Sometime preliminary test before other investigations (histology)
- Higher inadequate and error rates
- Used to confirm/exclude cancer/dysplasia and not to diagnosis with accurracy
What is the difference in staining between acute and chronic inflammation?
Acute–> more nucleotide polymorphs (tri lobed nucleus)
Chronic–> darker staining–> lymphocytes
What is the difference between Leiomyosarcoma and leiomyoma?
- Leiomyosarcoma–> Bulky, invasive masses in uterine wall or polypoid masses projecting into uterine lumen
- Leiomyomas –> within the uterine wall or bulging into the lumen–> not invasive
What is a Reed Sternberg cell of Hodgkin’s lymphoma?
Type of malignant cell
Looks like Owl face
Two nuclei in cell due to division
