L2: Lesion Classification And Characteristics Of Malignancy Flashcards
Chars. And types Of cystic lesions
-contain fluid and/or degraded amorphous cellular material (ie. Keratin, apocrine, or sebaceous)
Keratin-filled cyst characteristics
- also called epidermal inclusion or follicular cyst
- contain keratinized cells, amorphous material, and cholesterol crystals
- caseous appearance grossly
- blue “shmoo” in the background
- may become inflamed if ruptured (neuts react to keratin)
- self-trauma can lead to pyoderma
- very similar to interdigital furunculosis
Chars. Of apocrine cysts
- acellular, proteinaceous background
- colorless to brown fluid
- mass deflates when aspirated (but may recur)
- site predilection for head/neck
Chars. Of sebaceous cysts
- acellular, proteinaceous background
- oily to brown-tinged fluid
- mass may deflate when aspirated
- site predilection for head/neck
Hemorrhagic lesion characteristics
- numerous erythrocytes and/or hemoglobin in background WITH evidence of chronic hemorrhage
- macs containing RBCs and/or RBC breakdown products (hemosiderin and hematoidin)**
- hemosiderin looks black, hematoidin looks rust colored
Hemorrhagic Lesions
- hematoma
- seroma
- hemangioma
- hemangiosarcoma
chars. Of Inflammatory lesions
- increased leukocyte numbers
- classified based on inflammatory cells present:
1) neutrophils
2) neutrophils and macrophages
3) eosinophils
4) lymphoplasmacytic
5) mixed - type of inflammation can suggest underlying cause
- may need to request concurrent CBC
Chars. Of neutrophilic inflammatory lesion
- suppurative or purulent
- > 85% neutrophils
- degenerate or non-degenerate changes
- if degenerate, will see karyolysis, karyorrhexis, pyknosis
- causes: infection (abscess), sterile inflammation, immune-mediated disease, neoplasia
- must see intracellular bacteria to call it a true bacterial infection
Karyolysis
Nuclear fading; chromatin dissolution due to action of DNAses and RNAses
- leads to cell swelling
- always abnormal! Whereas pyknosis and karyorrhexis can happen with normal cell death
Pyknosis
Nuclear shrinkage; DNA condenses into shrunken basophilic mass
Karyorrhexis
Nuclear fragmentation; pyknotic nuclei membrane ruptures and nucleus undergoes fragmentation
Toxic vs. degenerative changes: what does it affect, where does change occur, and what does it indicate?
Deg. Change affects nucleus, change occurs within tissues, and indicates cell death, karyolysis, +/- infection.
Toxic change affects cytoplasm, change occurs within bone marrow, and it indicates inflammation or infection. Often seen in peripheral blood; occurs when cells are forming
Chars. Of neutrophilic and macrophagic inflammatory lesion
- pyogranulomatous
- neutrophils, with >15% macs*
- causes: FB, injection rxn, panniculitis (inflammation of fat), furunculosis, fungal/protozoal/certain bacterial infection (mycobacteria, nocardia, actinomyces)
- usually indicates a more chronic process
Most common vaccine rxn
Rabies (due to adjuvant used in vaccine)
-lepto rxn less common, but more severe
Magenta globular material can be:
Vaccine adjuvant
Ultrasound gel
Stain for mycobacterium
Acid fast stain (turns red)
Characteristics of lymphoplasmacytic inflammatory lesions
Can be mixed or monomorphic
-monomorphic lymphoid population without other inflammatory cells suggests neoplasia.
-MIXED lymphoid population caused by antigenic/immune stimulation (ie. Vax rxn), early viral infection, chronic inflammation, regressing histiocytoma
Chars. Of neoplastic lesions
- monomorphic population of cells
- benign or malignant
- has tissue of origin
- malignant neoplasia has >3 characteristics of malignancy
8 characteristics of malignancy
1) anisokaryosis (variation in nuclear size)
2) pleomorphism (variation in nuclear size and shape)
3) high/variable N:C ratio
4) mitotic figures (organization and separation of nuclear chromatin)
5) prominent nucleoli
6) coarse/clumped chromatin
7) nuclear molding (nuclei which distort or compress adjacent nuclei)
8) multinucleation
Chromatin patterns
- smooth or fine
- finely stippled
- lacy (reticular)
- coarse
- clumped
- smudged
chars. Of Hyperplasia or benign neoplasia
- have less than 3 characteristics of malignancy
- uniformity in nucleus: cytoplasm ratio
- minimal pleomorphism and anisokaryosis
- consistent size, shape, and number of nucleoli (some exceptions)
Exceptions to criteria of malignancy
Round cell neoplasms can have normal N:C ratio and nuclear features
Tissue architecture may be required for neuroendocrine, certain mesenchymal neoplasms (leiomyoma/sarcoma, myxoma/sarcoma), and certain epithelial neoplasms (basilar, mammary, hepatic, hepatoid)
Mixed cell neoplasms chars.
- contain inflammatory and non-inflammatory cells (epithelial, mesenchymal, etc.)
- reactive hyperplasia occurs in response to inflammation; cytology can mimic malignancy
- may need histopath for definitive dx
5 categories of tissue lesions
- cystic
- hemorrhagic
- inflammatory
- neoplastic
- mixed cell population
