L2: Lesion Classification And Characteristics Of Malignancy

Question 1

Chars. And types Of cystic lesions

Answer 1

-contain fluid and/or degraded amorphous cellular material (ie. Keratin, apocrine, or sebaceous)

Question 2

Keratin-filled cyst characteristics

Answer 2

• 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

Question 3

Chars. Of apocrine cysts

Answer 3

• acellular, proteinaceous background
• colorless to brown fluid
• mass deflates when aspirated (but may recur)
• site predilection for head/neck

Question 4

Chars. Of sebaceous cysts

Answer 4

• acellular, proteinaceous background
• oily to brown-tinged fluid
• mass may deflate when aspirated
• site predilection for head/neck

Question 5

Hemorrhagic lesion characteristics

Answer 5

• 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

Question 6

Hemorrhagic Lesions

Answer 6

• hematoma
• seroma
• hemangioma
• hemangiosarcoma

Question 7

chars. Of Inflammatory lesions

Answer 7

• 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

Question 8

Chars. Of neutrophilic inflammatory lesion

Answer 8

• 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

Question 9

Karyolysis

Answer 9

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

Question 10

Pyknosis

Answer 10

Nuclear shrinkage; DNA condenses into shrunken basophilic mass

Question 11

Karyorrhexis

Answer 11

Nuclear fragmentation; pyknotic nuclei membrane ruptures and nucleus undergoes fragmentation

Question 12

Toxic vs. degenerative changes: what does it affect, where does change occur, and what does it indicate?

Answer 12

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

Question 13

Chars. Of neutrophilic and macrophagic inflammatory lesion

Answer 13

• 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

Question 14

Most common vaccine rxn

Answer 14

Rabies (due to adjuvant used in vaccine)

-lepto rxn less common, but more severe

Question 15

Magenta globular material can be:

Answer 15

Vaccine adjuvant

Ultrasound gel

Question 16

Stain for mycobacterium

Answer 16

Acid fast stain (turns red)

Question 17

Characteristics of lymphoplasmacytic inflammatory lesions

Answer 17

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

Question 18

Chars. Of neoplastic lesions

Answer 18

• monomorphic population of cells
• benign or malignant
• has tissue of origin
• malignant neoplasia has >3 characteristics of malignancy

Question 19

8 characteristics of malignancy

Answer 19

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

Question 20

Chromatin patterns

Answer 20

• smooth or fine
• finely stippled
• lacy (reticular)
• coarse
• clumped
• smudged

Question 21

chars. Of Hyperplasia or benign neoplasia

Answer 21

• 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)

Question 22

Exceptions to criteria of malignancy

Answer 22

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)

Question 23

Mixed cell neoplasms chars.

Answer 23

• 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

Question 24

5 categories of tissue lesions

Answer 24

• cystic
• hemorrhagic
• inflammatory
• neoplastic
• mixed cell population