HEMANGIOSARCOMA
+ Pathogenesis
- HSA is a malignant neoplasm arising from endothelial cells
- Dermal HSA accounts for 14% of primary HSA
- Vascular stasis, radiation therapy, trauma, and sun exposure are predisposing factors in humans
- HSA has been experimentally induced in dogs with UV radiation and solar radiation may be involved in spontaneous development of cutaneous HSA in dogs
+ Signalment
- Sex predisposition: male
- Breed predisposition: GSD, Boxer, Whippet, and Pit Bull Terrier
- Dermal HSA is usually rapidly growing solitary, poorly circumscribed mass with early ulceration and infiltration
- ≥ 1 cutaneous HSA may represent metastatic disease
- However, multicentricity is a feature of canine HSA with up to 18% of primary cutaneous HSA presenting with multiple lesions
+ Diagnosis
- Hemostatic disorders are common and coagulation profile and bleeding times should be assessed
- Staging is important to assess whether cutaneous lesions are primary or metastatic lesions from a primary HSA in the spleen, right auricle, or liver
+ Clinical Stage
- Clinical staging is based on location within the dermis or association with the dermis:
- Stage I: dermal
- Stage II: hypodermal
- Stage III: muscle
+ Treatment
- Wide surgical resection for stage I HSA
- Wide surgical resection (i.e., limb amputation) and adjunctive chemotherapy (i.e., doxorubicin, cyclophosphamide, and vincristine) for stage II and III HSA
- Radiation therapy is ineffective
+ Prognosis
- Prognosis is guarded
- 30% metastatic rate and MST 780 days for stage I HSA
- 10% metastatic rate and MST 172 days for stage II HSA
- 60% metastatic rate and MST 307 days for stage III HSA
- MST for hypodermal HSA following surgery and chemotherapy: 425 days
- Good prognostic factors in humans include small tumor size (< 5 cm) and lymphocytic infiltration around tumor
+ HEMANGIOMA
- No breed or sex predilection
- Gross appearance: solitary, well circumscribed, unencapsulated, red-to-black colour, and located in subcutaneous and dermoepidermal tissue
DERMAL HEMANGIOMA AND HEMANGIOSARCOMA
| T0 | No evidence of neoplasia | T1 | Tumor less tbaan 5 cm in diameter and confined to primary site - Primary Tumor |
| T2 | Tumor ≥ 5 cm in diameter, ruptured, or invading subcutaneous tissue |
| T3 | Tumor invading adjacent structures including muscle |
| M0 | No evidence of metastasis |
| M1 | Evidence of distant metastasis with site specified - Metastasis |
| N0 | No evidence of lymph node involvement |
| N1 | Regional lymph node involvement - Node |
| N2 | Distant lymph node involvement |
Clinical Stage
| I | II | III | T | T1 | T1-2 | T2-3 | N | N0 | N0-1 | N1-2 | M | M0 | M1 | M2 |