Cytology

• quick, easy, inexpensive • Non-invasive and minimal risk to patient • used as a screening tool to determine what diagnostic procedures should be performed next • useful in Dx or IDing disease process

• Reliant on sample quality (skill of collecter, smear quality, type of tissue [exfoliation], site of collection) • Experience/ability of person examining sample and quality of microscope • Lack of information about tissue architecture (histopath provides this) • Dx challenges of cytology

• more expensive procedure as sterile • slower turnaround (48hrs) • poor detail for round cell tumours (cytology better) • tissue architecture visable, tumour grading, immunohistochemistry more available

> Aspiration or imprints - superficial masses - LN enlargement/metastitis - Organs and deep masses with US guidance > Fluids - body cavities (peritoneum, pleural space, pericardium) - Joints - Respiratory tract (TTW, BAL) - Cerebrospinal fluid

solid/fluid filled masses • biopsy = aspirate but no negative pressure applied [no need really] • aspirate may be carried out only if biopsy not successful (ensure remove negative pressure on plunger before removing from mass or contents will be sucked into syringe) • only fill needle part of syringe, if fluid reaches syringe will probably be blood stained • necrotic centre masses = ensure wall is sampled as well as centre

• Thin areas with good cell spread • Minimise cell damage • Minimise blood content

Neoplastic cells AND lymphocytes

• Evaluating excised tissue or superficial lesions • Imprints made BEFORE tissue placed in formalin to go to histopath • Use fresh cut surface (cut sample in half if necessary) • Blot until dry with paper towel • Roll sample against slide • Air dry and stain

EDTA

Sterile

• Sample quality - enough cells, good condition, spreading, representative of lesion, normal cells as well as abnormal expected? • Inflammation v. neoplasia • Inflammatory = Septic v. Non-septic • Neoplasia = Round cell v. Epithelial v. Spindle cell • Neoplasia = Benign v. malignant

Sample dominated by inflammatory cells (neutrophils/eosinophils/lymphocytes/macrophages) or tissue cells (neoplasia)? > If both are present, need experience as could be inflammation with 2* dysplasia or neoplasia with 2* inflammation > biopsy required

> Septic: bacteria/organisms WITHIN neutrophils, if extracellular may be contaminant. degenerate neutrophils [lysed due to O* burst] Non-septic: No bacteria, no degenerate neutrophils.

• Nuclear change • Nucleus swells, loses lobulation and becomes paler (chromatin less condensed) • 2* to release of bacterial toxins • Degenerate neutrophils -> suspect septic cuases even if no bacteria seen

Pyknosis

Stain precipitate

Granulomatous inflammation eg. Mycobacterium sp or FB

Pyogranulomatous seen with fungal infections or FB

• Individual cells not clustered • Small/medium round/oval cells eg. medium lymphocyte = 2x RBC • Round/oval nuclei • Well defined cell borders • Good cell yield • Seen better with cytology than histopath

• Lymphoma • Plasmacytoma • Histiocytoma • Mast cell tumour • Transmisable venereal tumour (TVT) • Melanoma

• Sheets/rafts/clusters • Large cell size • Cell-to-cell junctions but good cell border • oval/angular shape • Nuclei round andcentral • Cytoplasm often abundant • Good cell yield • eg. sebaceous, mammary, liver

• Individual cells OR clumps • Small medium sized • Spindle/fusiform/stellate • Indistinct cell border but not joined like epithlium • Elongated nucleus • Poor exfoliation • Matrix production -collagen/ostoid

Benign: Adenoma Malignant: Carcinoma

Benign: Fibroma Malignant: Fibrosarcoma