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This article explores the process of cytological examination, including the evaluation of stained cells, identification of different cell types, and interpretation of inflammatory vs. non-inflammatory findings. It also discusses the importance of cytology in determining the next diagnostic steps, such as culture, biopsy, radiography, or serology. The article covers various classifications of inflammation and provides information on specific infectious agents and their cytological characteristics.
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Cytological Examination: Part II Clinical Pathology
Microscopic Evaluation • Scan at 10x • Determine if stained adequately • Any localized or increased cellular areas • Scan for any large objects: parasites, foreign bodies, etc. • Look at what type of cells are found • Examine at 40x • Evaluate individual cells • Examine at 100x (oil immersion) • Cell morphology, nucleus, chromatin, cytoplasm
Interpretation • Inflammatory vs. Non-inflammatory • Most important judgement • May not get a definitive diagnosis, but may be able to get a general idea/general process. • Cytology may be helpful on what’s the next diagnostic step to take • Culture • Biopsy • Rads • Serology
Inflammatory cells found in Cytology • Neutrophils • May resemble same as blood neutrophils. • Be degenerative • Hypersegmented • Lymphocytes • Plasma cells • Active lymphocytes that have a very basophilic cytoplasm • Eosinophils • Mast cells- allergic inflammation • Macrophages • Large tissue monocytes. • Have abundant blue cytoplasm with vacoules that may contain phagocytized cells or debris • Oval to pleomorphic nucleus • Mesothelial cells • Cells that line the pleural, peritoneal,a nd visceral surfaces. • A type of macrophage
Classifications of Inflammation • Purulent • Pyogranulomatous • Granulomatous • Eosinophilic • May also be classified as duration: • Acute • Subacute • Chronic-active • Chronic
Purulent Inflammation (Abscess) • Most common type of inflammation • Usually caused by bacteria • Also called suppurative inflammation • Over 70% neutrophils with a few macrophages and lymphocytes
Pyogranulomatous inflammation • Also referred to as chronic/active • Consists of macrophages and 50-75% neutrophils
Granulomatous Inflammation • Greater than 50-70% of cells are mononuclear (monocytes, macrophage, giant cells). • Few neutrophils • Also called chronic inflammation.
Eosinophilic Inflammation • Consists of greater than 10% eosinophils • Allergic related • May see a few mast cells, plasma cells and lymphocytes
Selected Infectious agents of Cutaneous lesions • Bacterial agents • Tend to produce lesions characterized by >85% neutrophils, few macrophages, lymphocytes, and plasma cells. • Rods, cocci • Cytology is helpful in determining what kind of culture or stain is needed. • Fungal agents • Tend to have more macrophages than bacterial lesions, but may be mixed (pyogranulomatous). Low numbers of lymphocytes. • Sporothrix schenkii • Histoplasma capsulatum • Blastomyces dermatidis • Crytococcus neoformans • Coccidiodes immitis
Sporiotrichosis: Sporothrix schenkii • Organisms are round to oval or cigar shaped • Stain pale to medium-blue cytoplasm with a slightly eccentric pink or purple nucleus. • Dimorphic fungus found in the environment worldwide • Inoculated into tissue via puncture wounds • Suppurative to pyogranulamatous • Skin lesions are characterized by multiple, non-painful, nonpruritic nodules that may ulcerate and drain purulent exudate. • Dissemination is rare
Sporotricosis continued • Diagnose via cytology, biopsy, fungal culture • Easier to diagnose in cats, tend to have more organisms • Infected cats are highly contagious to humans • Treatment includes long term antifungals • Ketoconazole • Itraconazole • Prognosis is fair to good, but relapse is possible.
Histoplasma Capuslatum • Round to oval- yeast-like • Dark blue/purple staining nucleus surrounded by a thin halo • Causes systemic disease • Cutanous lesions are rare, causes lungs or GI tract infections • Most common in termperate and subtropical areas. • Diagnosed through cytology, histopathology, fungal cultures, rads
Blastomyces dermatidis: Blatomycosis • Caused by inhaling the conidia • Causes a disseminated infection • Lymph nodes • Skin • Bones • Other organs • Found in mostly acidic soils • Diagnosed by cytology, histopathology, serology and fungal cultures. • Most are single, blue, spherical and thick walled. • Pyogranulamatous
Cyptococcus Neoformans: Cryptococcosis • Found worldwide • Organism is inhaled and establishes infections in the nasal cavity, sinuses, skin and other organs • Spherical, yeast-like organisms • Thick, clear mucoid capsule • May be budding or non-budding • Cats: URI signs, SQ swelling over bridge of nose, non-painful, may have CNS signs • Dogs: CNS signs and ophthalmic signs usually occur. Nodules on lips and nose.
Coicidiodes Immitis: Coccidiomycosis • Dimorphic fungus and soil saprophyte endemic to desert areas • Organisms are inhaled and disseminate in body • Skin lesions are nodular, abscesses and draining tracts • Painful lameness
Coccidiomycosis Continued • Spherical with thick deeply stained wall. • Diagnosis thought cytology, pyogranulamatous, histopathology, serology and fungal culture. • Treated by long term systemic antifungals (8-12 months) • Prognosis is unpredictable • Relapses are common • Fungal cultures are contagious • Infected animals are not considered contagious
Leishmania donovani: Leishamaniasis • Protozoa transmitted by blood-sucking sandflies • Endemic to Central and South America • Sporadic infections in the US • A visceral and cutaneous disease that develops over months-years • Lesions are dark and small to large and ulcerated. • Diagnose by imprints, scraping and FNA • Organism usually found in macrophages • Small, round to oval • Has a very light blue cytoplasm, an oval nucleus, and a small dark kinetoplast • Usually numerous organisms found • Not curable • Contagious to other dogs through vector
Non-inflammatory Lesions • Neoplastic • Epithelial • Mesenchymal (spindle cell) • Discrete Round cell tumor • Non-Neoplastic • Cysts (sebaceous) • Hyperplasia (prostatic hyperplasia) • Dysplasia • Hematomas • Seromas • Salivary Mucocele
Epithelial Neoplasms • Tend to exfoliate cells in sheets or clumps • Cells tend to be large with moderate to abundant cytoplasm • Benign epithelial tumors • Papilloma • Epidermal inclusion cyst (epithelioma) • Perianal gland adenomas • Malignant epithelial tumors • Perianal gland adenocarcinoma • Squamous cell carcinoma
Mesenchymal tumors: Spindle cell tumors • Tend to exfoliate individual cells instead of clusters • May be difficult to differentiate from normal granulation tissue (spindle cells are plump). • Difficult to differentiate from the different types of tumors on cytology. • Benign forms: • Fibromas • Lipomas • Hemangioma • Malignant forms: • Fibrosarcoma • Liposarcoma • Hemangiosarcoma
Discrete Round Cell Tumors • Tend to exfoliate small to medium sized cells. • Also called cutaneous round cell tumors • Types: • Mast cell tumors • Cutaneous lymphosarcoma • Histioctyomas Transmissable venereal tumor
Evaluation of Malignant Potential (Criteria of Malignancy) • Variation of cell size • Variation in nuclear size • Multinucleated • Increased nucleus: cytoplams ratio • Mitotic figures • Variation in nucleolar size/shape • Coarse Chromatin pattern • If more than 3 criteria are recognized in a high percentage of cells, this is strong evidenc for malignancy • If 1-3 criteria are present, may be either benign or malignant and should be sent to pathologist or biopsied.
Submission of Cytologic Slides • Send 2-3 air-dried unfixed smears and 2-3 stained smears • Fluid samples should have smears prepared from them immediately • Also send EDTA and red top tubes filled with fluid • Mail in protective containers • Timely transportation service • Easy accesible and easy to collect cytology • Tranquilization/anesthesia seldome needed for sample collection • Quick-sample can be prepared, stained, and microscopically evaluated in minutes.