Histo: Fundamentals of Histology (Emily) Flashcards
What is the shape of neutrophils?
Polymorphic, multilobulated, lobular nucleus, many granules
- What type of inflammation are neutrophils important for?
Acute inflammation
Give examples of pathologies associated with neutrophilic infiltrate.
Acute appendicitis
Acute salpingitis
Cellulitis
What cells are key for chronic inflammation?
Lymphocytes and plasma cells
What cancers are associated with high lymphocyte and high neutrophil count respectively?
Chronic infection and Lymphoma = high lymphocytes
Myeloid leukaemia = high neutrophils
What infection may cause high lymphocytes and neutrophils?
Helicobactor infection
What sort of inflammation may be seen in UC and what cells can be seen in the histology of the GIT?
Acute on chronic inflammation may occur. Pt may have acute exacerbations on top of chronic inflammation. Histology may show many plasma cells and lymphocytes, but also many neutrophils in the crypts.
How may you differentiate between inflammation or a lymphoma on histology showing many lymphocytes?
Lymphoma cells all look the same due to clonal differentiation. Inflammation will show mix of cells.
Describe the shape of Eosinophils.
They have granules and bilobed nuclei.
What are Eosinophils associated with?
Allergic reactions
Parasitic infections
Tumours e.g. Hodgkin’s disease
What is the most common cause of oesophagitis?
Reflux.
What does eosinophilic oesophagitis suggest?
Reflux causes acute inflammation so you would expect neutrophils to be seen on histology. EO suggests an allergic reaction to food that has come in contact with the oesophagus in the same way that asthma is due to allergy to allergens in the air.
Describe what mast cells look like.
Have many granules which contain inflammatory mediators
What sort of allergic reactions are mast cells important for?
Type 1 allergic reactions such as urticaria.
What is the role of macrophages?
Macrophages are cells that clear up the debris following inflammation. Acute inflammation = neutrophil phase. Macrophages come in afterwards. If the inflammation persists and becomes chronic, lymphocytes begin to dominate.
What sort of inflammation are macrophages associated with?
Late acute inflammation Chronic inflammation (including granulomas)
What is a special type of chronic inflammation associated with macrophages?
Granulomatous inflammation
What is characteristic of TB histology?
Loads of granulomas. Giant cells are formed by fusion of macrophages. There is necrosis in the middle of granulomas - cheesy necrosis is characteristic of TB
What is a granuloma?
Organized collection of activated macrophages. An organized collection of activated epithelioid macrophages. Epithelioid activated macrophages are involved in secretion of cytokines and they cluster together to form granulomas.
What are causes of granuloma formation?
TB, sarcoid, infectious causes, reaction to tumours
What test is used to confirm TB?
Acid-fast staining (Ziehl-Neelson stain)
Give 4 types of tumours and the cells they are derived from.
Carcinomas = malignant tumours of epithelial cells
Sarcomas = malignant tumours of mesenchymal cells, connective tissue (muscle, bone, cartilage)
Lymphoma = malignant tumours of lymphocytes
Melanoma = malignant tumour of melanocytes
If it ends in sarcoma or carcinoma means it is malignant. Ends in -oma means benign.
What are the 3 main types of carcinomas?
Squamous cell carcinoma
Adenocarcinoma
Transitional cell carcinoma
Where are common places for squamous carcinoma?
Skin, head and neck, oesophagus, anus, cervix, vagina
What do squamous cell carcinomas make?
Keratin
What are adenocarcinomas derived from and where are they found?
Glandular epithelium. These tumours make glands and secrete mucin. Found in the lung, breast, stomach, colon, pancreas.
Where do transitional cell carcinomas occur?
Most commonly in the urinary system, kidneys, ureters, bladder.
What are key histological features of SCC?
High nuclear : cytoplasm ratio
Variable sizes of nuclei
Intercellular bridges (from keratin)
What cells are melanomas derived from?
Melanocytes. Some melanomas become so poorly differentiated that they stop secreting melanoma and become amelanotic melanomas.
What stain is used for detecting melanin?
Fontana stain
What are the two types of stains?
Histochemical - based on a chemical reaction between the stain and a specific component of the tissue. Examples: Fontana stain for melanin, Prussian blue for iron.
Immunohistochemical - based on using an antibody specific to an antigen in the tissue. Need a detection system to make this binding visible. Gives ability to recognise a lot of structures.
What stain is used to diagnose amyloid?
Congo Red stain
What do you see if you take a congo red section stained tissue with amyloid and examine it under polarized light?
Apple green birefringence in amyloid
What are the main steps in immunohistochemical staining?
Primary antibody, secondary antibody then add detection system
How does the treatment of carcinoma differ from lypmhoma?
Carcinomas are cured mainly by surgery. Lymphomas are more amenable to immunohistochemical staining and treatment
What stain can be used to detect epithelium cells (and therefore carcinomas)?
Stain for cytokeratins, an epithelial marker. Different epithelial cells have different types of cytokeratins.
What is a marker for lymphocytes (and therefore lymphomas)?
CD45
What may you expect to see on histology of oesophagus with herpes simplex?
Multinuclear giant cells
How can you diagnose HSV from a biopsy?
Immunohistochemistry using herpes antigens
