Cytopathology Flashcards
Serous membrane
- Structure
- Function
- Examples
Two layers of cells that are composed of mesothelial cells.
- Secretes small about of serous fluid to lubricate cavity
- Any effusion is pathological.
Inner layer= visceral
- Lines body cavity
Outer layer= Parietal
- Lines body wall
Examples
- Thoracic (pleura)
- Pericardium
- Tunica vaginalis (penis)
- Abdominal
Formation and reabsorption of serous fluid
Capillaries in serous membrane are under hydrostatic and oncotic pressure
Fluid is reabsorbed into lymphatics, capillaries and venules
Transudate
- Formation
- Appearance
- Cells
- Examples
Plasma ultrafiltrate
- High hydrostatic, low oncotic
Appearance
- Clear, pale yellow
- Low protein, <3g/dL
- Does not clot
Cells= very few
- Deranged mesothelial
- Few lymphocytes, macrophages
Examples
- Cardiac
- Cirrhotic
- Nephrotic
- Hypoproteinaemia
Exudate
- Formation
- Appearance
- Cells
Unfiltered plasma
- Due to changes in vascular permeability
Appearance: cloudy/ yellow/ bloody. High protein (>3g/dL), clots
Many cells
- Inflammation
- May be malignant
Indications of pale yellow and watery effusion
Transudate
- CCF
- Cirrhosis
- Hypoproteinaemia
Indications of turbid+ yellow-white effusion
- Infection
- Malignancy
- Pancreatitis
Indications of milky white / greenish effusion
Chylous effusion from thoracic duct obstruction (trauma, lymphoma)
Indications of Milky green with a silky sheen effusion
Pseudochylous effusion caused by cholesterol from
- TB
- rheumatoid disease
- old effusion
Indications of a brown effusion
- Haemorrhage (trauma pancreatitis malignancy)
- Melanin
Indications of a green effusion
Bile from biliary tract disease or ruptured bowel
Indications of a gelatinous effusion
- Hyaluronic acid from mesothelioma
- Mucin in pseudomyxoma
Mesothelial cells
- N:C ratio
- Appearance
Make up serous membrane
N:C ratio is variable
- Can have multiple nuclei
Perinuclear cytoplasmic density
Peripheral lacy border
Macrophages
Usually present in effusion
- Foamy pale cytoplasm
- Bean shaped nucleus
Lymphocytes in effusions
Present, but few
If pathological
- Obstructed circulation from lymph nodes: TB, lyphoma
Neutrophils in effusions
May be present
Indications
- Infection: often degenerate
- Infarction
- GI disease
- Foreign body
- Early TB
- Tumour- usually benign.
Eosinophils in effusions
- Location
- Indications
Often idiopathic
- Mainly in pleura
Indications
- Air in pleura (increases with aspiration)
- Infection
- Infarction
- Drugs
- Dialysis
- Allergies, asthma
- RARE- Hodgkins
LE cells
Lupus erythematous cell
A neutrophil/ macrophage that has phagocytosed a nucleus of another cells
Features of malignant cells in effusions
- Nucelus
- Cytoplasm
Groups: clumps, balls papillae, glands.
Single= dispersed
Cell nuclei
- Large
- Larger N:C ratio
- Irregular membranes
- Coarse, irregular chromatin
Cytoplasm
- Vacuoles
- Mucin/ melanin/ keratin
Breast Cancer cell features
DIFFUSE cell pattern
Groups
- Small single cells of lobular carcinoma
Cytoplasm
- Intracytoplasmic lumina, may dilate
- Microvilli and mucin
- Indian files
Lung Cancer cell effusion features
Different patterns of differentiation
Groups- papillary
Cytoplasm
- Dense
- Can be highly vacuolated
Stomach cancer cell effusion features
- Cell pattern
- Cell types
Pattern
- Usuually dispersed, single
- May form papillae/ acini
Signet ring (cell with large vacuole)/ columnar cells
Colorectal cancer cell effusion features
- Cell pattern
- Cell types
- Nucelus
Pattern
- Papillary + acinar
Cells
- Columnar
Nucleus
- Palisades with nuclear membrane
Features of mesothelioma
- Pleura
- Uni or bilateral?
- Fissures
Nodular pleural thickening, diffuse
Unilateral
Thickening of fissures
Features of fixing sample with alcohol
See nucleus in more detail
Cells are transparent, can see keratinisation
Can see
- Squamous differentiation
- Hyperchromasia
- necrosis
Stain: H+E
