Oncology Flashcards
Study and Treatment of Cancer
* disease caused by uncontrolled divison of abnormal cells in parts of the body
* abnormal cells fail to die
Classification of Tumors
- Benign vs Malignant
- Tissue of origin
Cancer Developement
Normal cells will have regulated cell division and apoptosis (removes abnormal cells)
Cancer happens when:
* apoptosis is interrupted
* abnormal cells get past and growth continues unchecked
* requires multiple mutations
Apoptosis
Death of cells
* normal and controlled part of an organism’s growth or development
Cancer Growth
- Interruption of apoptosis
- Abnormal loss of cell-to-cell adhesion - cancer cells go anywhere they want
- Overexpression of growth factors
- Formation of new blood vessels
- Evasion of immune system
Benign Cancers
- Grow slowly
- Encapsulated
- No metastases
- Can cause clinical signs if impinging on surrounding tissues
- Can not differentiate benign neoplasia from hyperplasia without pathology
Malignant Cancer
- Grows rapid
- Invades and destroys normal tissue
- Causes inflammation and easily infected
- Metastasizes through blood and lymphatic vessels
- Show clinical signs at primary and secondary sites
Paraneoplastic Syndromes
Secondary effect from tumors secreting certain chemicals
* hypercalcemia
* hypertension
* low BG
Tumor Staging
- Do in clinic
- How far and deep a tumor has spread
- Various diagnostic tests done
Tumor Staging
Diagnostic Tests
- Calipers: size of extenal tumors
- Radiographs: size of internal tumors / metastasis check
- Ultrasound: check liver and spleen
- BW: should be normal unless paraneoplastic syndome present
- LN Cytology: see if cancer spread to LN
Tumor Grading
Score based on certain factors (high grade more aggressive)
* Done through histophathology
* mitotic activity
* vascular or lymphatic invasion
* cellular appearance
* nuclear characteristics
Tumor Classification by Origin
- Estimated by cytology, diagnosed by histology
- May require certain stains
- Types are: Epithelial, Mesenchymal, Discrete Round Cell
Epithelial Tumors
- Lines skin, MM, glandular structures
- Benign = adenoma
- Malignant = carcinoma / adenocarcinoma
Identify Tumor
Epithelial Tumor
* Large round / caudate cells
* Highly cellular samples
* Exfoliate in clumps or sheets
* May have vacuolization if glandular origin
Mesenchymal Cell Tumors
- Come from connective tissues, bone, muscle
- Differentiate done via histology
- -oma vs -sarcoma
- Locally invasive
- Variable metastssis rate
- Surgery recommended
Identify Tumor
Mesenchymal Cell Tumors
* small / medium spindle shaped cells
* low cellularity (cluster / high number is severe)
* exfoliate singly
Identify Tumor
(general)
Discrete Round Cell Tumors
* Small / medium round cells
* Highly cellular sample
* Do not exfoliate in clumps or clusters
Identify Tumor
Histiocytoma
* Discrete Round Cell Tumor
* See in young dogs (<4)
* Benign, fast growing
* Solitary, button-like pink nodules
* May randomly disappear in 3 months
Identify Tumor
Plasma Cell Tumor
* Discrete Round Cell Tumors
* Benign: plasmacytomas (look like histiocytomas)
* Malignant: multiple myeloma (affects BM)
* Golgi apparatus in cytoplasm
* More likely to have multi-nucleation (despite being benign)
Identify Tumor
Mast Cell Tumor
* Discrete Round Cell Tumors
* Mimic appearace of other tumors
* Contain histamine, heparin, serotonin
* Degranulation (give antihistamine before poking)
* Avoid morphine (causes histamine release)
* Dogs: need histopathology to determine grade
* Cats: generally benign (remove only if bothers)
* Remove with wide margins + chemo
Identify Tumor
Transmissible Venereal Tumor
* Discrete Round Cell Tumor
* On base of penis, prepuce or vulva only in dogs
* Associated with breeding
* Chemo +/- surgery
Non-malignant Mass
Inclusion Cysts
* Abundant of mature cornified squamous cells
* Background of keratin and cellular debris
Non-Malignant Mass
Salivary Mucocoele
* Benign accumulation of saliva
* Thick fluid
* Windrowing of cells
* Moderate amount of WBC
* Few macrophages (vaculated; dark cytoplasm)
* Few neutrophils
