Exam 7 L .11 Flashcards Preview

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Flashcards in Exam 7 L .11 Deck (13):
1

Spleen masses-dogs

Benign disease is more common

2

Hemangiosarcoma

1) malignancy of vascular endothelial cells
2) 2% canine cancer
3) higher incidence in German shepherds, golden retrievers, labradors
4) arises anywhere: most common is skin, subcutaneous, spleen, liver, and right atrium or auricle
5) synchronous disease-multiple primary sites
6) biological behavior aggressive in all forms except superficial epidermal form
7) 2/3 splenic masses are malignant, 2/3 HSA
8) suspicion of spleen HSA: splenomegaly and anemia, hemoabdomen, increased nRBC

3

HSA spleen presenting signs

1) Nonspecific-lethargy, anorexia, weakness, weight loss
2) Specific signs: acute weakness, sudden collapse/death, exercise intolerance, abdominal effusion/mass, hypovolemic shock
3) weakness and abdominal distention may wax/wane
4) regenerative anemia, increased nucleated RBC, polychromasia, thrombocytopenia
5) up to 1/3 dogs with spleen HSA have subclinical DIC*

4

Diagnosis of HSA

1) ultrasound-guided FNA may be dangerous if cavitated
2) coagulation panel
3) abdominal or pericardial tap, cytology, PCV
-blood from hemoabdomen shouldn't clot

5

Traditional therapy: HSA

1) surgical excision: splenectomy, right atrial appendage removal, subcutaneous mass excision
2) 1/3 of dogs with spleen HSA have arrhythmias
3) no patient should be euthanized because of hemoabdomen alone-histopathology needed to confirm
4) cardiac troponin I concentration allows differentiation of cardiac HSA from HSA at other locations

6

Survival after splenectomy

1) approximately 1-3 months survival with surgery alone (splenectomy)
2) systemic therapy-chemotherapy with doxorubicin
- approximately 6 months survival time

Note: it's a surgical disease ==> we want to remove the tumor

7

Prognosis

1) doxorubicin postop for any location will improve survival!
2) poor prognosis: cardiac mass, collapse, hemoabdomen*, advanced clinical stage, multiple nodules

8

2 skin presentations

1) thin haired regions: solar induced inguinal/abdomen
-strawberry like lesion, multiple, diffuse
2) cutaneous prepucial, abdomen
-postsurgical MST 2 years of superficial (dermal)
3) if deeper, subcutaneous tissues, then 4-10 months
-chemotherapy increases survival

9

Cats

1) in cats, mast cell tumor and lymphoma are common malignant causes of diffuse splenomegaly
2) spleen masses may be hemangiosarcoma or similar DDX as dogs
3) skin HSA: UV induced-metastasis uncommon, locally recurrent
-if not caused by solar exposure and no metastasis, then aggressive surgery

10

Remember

Tumor growth is halted when malignant cells are located more than 100-200 um from blood vessels, which is the limit for diffusion of oxygen*

11

Chemotherapy for anti-angiogenesis

1)**ultra low dose, daily chemotherapy (metronomic)
-inhibits vascularization of islands of tumor cells
-dose is too low to damage the actual tumor cells
-much less potential toxicity!
-The tumor might be resistant to high-dose chemo, but we might be able to inhibit metastasis!

12

Metronomic chemotherapy

1) low dose cyclophosphamide and piroxicam
-decreases circulating endothelial progenitor cells
-increases anti-angiogenesis factors
2) no survival advantage when compared with doxorubicin given post splenectomy

13

Spleen masses-dog

1) benign disease is more common: hematoma, hyperplastic nodule, abscess, extra medullary hematopoiesis, granuloma in more than 50%
2) primary spleen tumors: hemangiosarcoma, fibrosis, histiocytic sarcoma, leiomyosarcoma, hemangioma, osteosarcoma