Skin and mammary gland tumors; mastectomy

Question 1

Determination of the extent of the disease
locally, regionally and distantly is called

Answer 1

clinical staging.

Question 2

MCTs is less likely to metastasize into the

Answer 2

lungs.

Tends to expand locally unless removed completely.

Question 3

Clinical staging involves (3)

Answer 3

• Measurement of the (longest) diameter (determination of local extent of disease
• Evaluation of all lymph nodes in the region via Cytological/histological samples (determination of regional extent of disease)
• Diagnostic imaging (CT, MRI, X-R, ultrasound)
  – results often increase the stage (determination of distance extent of disease)

Question 4

If you have a skin tumor, its most likely to be?

Answer 4

a mast cell tumor

If you have a strong suspicion of MCT, you can inject the tumor with ranitidine antihistamine before taking FNA to try to avoid a big histamine release reaction.

Question 5

Most likely cause of fibrosarcoma in cats

Answer 5

rabies vaccine, injection site sarcoma

Question 6

Systemic tumor treatment depends on the case and can be combined with surgery. WHat 3 systemic tx are there

Answer 6

• Chemotherapy
• Radiation therapy
• Hormonal therapy

Question 7

After excision of a neoplasm, what should you do before closing?

Answer 7

• Before closure, gloves and instruments should be changed.

• Elliptical incision
• ~1-3 cm of normal skin excised with the neoplasm

Question 8

How big should your margins be when excising a neoplasm?

Answer 8

~1-3 cm of normal skin excised with the neoplasm

Question 9

Minimal database for staging when presented with mammary region neoplasia:

Answer 9

• Complete blood count, biochemistry
• Three-view thoracic X-Ray (CT more sensitive)
• Fine needle aspirate (regional lymph nodes; neoplasia?)

Later: Definitive diagnosis – histopathology (all masses)

Question 10

Differenital diagnoses for mammary neoplasia (6)

Answer 10

• Mastitis (difficult to differentiate from inflammatory carcinoma)
• Dermatitis
• Mammary hyperplasia/dysplasia
• Tumors of the skin and subcutaneous tissues
• Granulomas
• Foreign bodies

Question 11

Define:
* Lumpectomy
* Simple mastectomy
* Regional mastectomy
* Unilateral mastectomy
* Bilateral mastectomy

Answer 11

• Lumpectomy - removal of a mass or part of a mamma (mostly advisable to avoid, because milk and lymph leakage may cause inflammation)
• Simple mastectomy - excision of an entire gland
• Regional mastectomy - excision of the involved gland and adjacent glands
• Unilateral mastectomy - the removal of all mammary glands, subcutaneous tissue, and associated lymphatics on one side of the midline
• Bilateral mastectomy - simultaneous removal of both mammary chains (preferably staged unilateral)

Question 12

What type of mastectomy for cat with 1 tumor?

Answer 12

• Chain (unilateral) mastectomy in cats even with
  only 1 tumor (local recurrence decreased)

Question 13

Mammary gland anatomy in dogs vs cats.

Answer 13

• Compound, tubuloalveolar, apocrine glands
• Usually 5 pairs of mammary glands in dogs, 4 pairs in cats.

Question 14

Major blood vessels suppling the mammary glands of dogs and cats.

Answer 14

caudal epigastric prob being the largest

Question 15

Criteria used for histologic grading of malignancy in cat and dog mammary carcinomas. (3)

Answer 15

tubule formation
nuclear pleomorphism
mitoses/10 per high power field

Question 16

what do mitoses tell you in histology of neoplasms?

Answer 16

used to assess how actively cells are dividing, which can be an important indicator in diagnosing tumors and assessing their aggressiveness.

A higher mitotic count usually suggests a more aggressive or fast-growing tumor.

Question 17

what is tubule formation in histologic grading of malignancy?

Answer 17

It refers to how much of the tumor is forming glandular or tubular structures—which are typical of normal, healthy glandular tissue.

Normal glandular tissue forms well-defined tubules (small tube-like structures lined by epithelial cells).

Well-differentiated tumors retain this tubule-forming ability, mimicking normal tissue architecture.

Poorly differentiated tumors lose this structure and grow in solid sheets or irregular clusters, indicating a higher grade and more aggressive behavior.

Question 18

why should you care about Nuclear pleomorphism (variation in nuclear size/shape) in histologic grading of malignancy?

Answer 18

because it reflects how abnormal or aggressive a tumor is.

Normal cells have uniform, small, round nuclei.

Malignant cells often have large, irregular, and variable nuclei, a sign that the cells are losing their specialized functions (i.e., they are poorly differentiated).

More pleomorphism = more abnormal = higher grade tumor.

Tumors with marked nuclear pleomorphism tend to grow faster, invade more readily, and metastasize earlier.

Therefore, higher pleomorphism usually predicts a worse prognosis.

Question 19

ionzing radiation is most likely to cause what type of neoplasia in which species

Answer 19

squamous cell carcinoma in cats, espesh white cats