Embedded Files
General Principles & Management
General Principles & Management
• Etiology: Driven by environmental factors (solar, chemical, radiation), biological factors (viruses, hormones), and genetics.
• Etiology: Driven by environmental factors (solar, chemical, radiation), biological factors (viruses, hormones), and genetics.
• Classification:
• Classification:
◦ Benign: Localized, encapsulated, non-infiltrative.
◦ Benign: Localized, encapsulated, non-infiltrative.
◦ Intermediate Malignancy: Locally infiltrative and difficult to excise, but seldom metastasize.
◦ Intermediate Malignancy: Locally infiltrative and difficult to excise, but seldom metastasize.
◦ Malignant: Highly infiltrative with high metastatic potential.
◦ Malignant: Highly infiltrative with high metastatic potential.
• Surgical Strategy:
• Surgical Strategy:
◦ First Surgery: Crucial for success; "octopus-like" tentacles often extend deep into tumor beds.
◦ First Surgery: Crucial for success; "octopus-like" tentacles often extend deep into tumor beds.
◦ Margins: 3 cm typically recommended for most malignancies; 5 cm lateral margins and two fascial layers are required for Feline Injection Site Sarcomas.
◦ Margins: 3 cm typically recommended for most malignancies; 5 cm lateral margins and two fascial layers are required for Feline Injection Site Sarcomas.
• Diagnostics: Cytology (FNA) for screening; Histopathology for definitive grading; Immunohistochemistry/Molecular diagnostics to identify biomarkers for treatment.
• Diagnostics: Cytology (FNA) for screening; Histopathology for definitive grading; Immunohistochemistry/Molecular diagnostics to identify biomarkers for treatment.
Connective Tissue Tumors (Mesenchymal)
Connective Tissue Tumors (Mesenchymal)
• Benign Fibroblastic:
• Benign Fibroblastic:
◦ Collagenous Nevi: Focal developmental defects; common in older dogs.
◦ Collagenous Nevi: Focal developmental defects; common in older dogs.
◦ Generalized Nodular Dermatofibrosis: Inherited in German Shepherds; associated with renal cystadenocarcinomas.
◦ Generalized Nodular Dermatofibrosis: Inherited in German Shepherds; associated with renal cystadenocarcinomas.
◦ Acrochordons (Skin Tags): Benign pedunculated growths in older dogs.
◦ Acrochordons (Skin Tags): Benign pedunculated growths in older dogs.
◦ Fibromas: Discrete dermal nodules; common in Dobermans and Boxers.
◦ Fibromas: Discrete dermal nodules; common in Dobermans and Boxers.
• Soft Tissue Sarcomas (STS):
• Soft Tissue Sarcomas (STS):
◦ General Characteristics: Morphologically heterogeneous; difficult to distinguish cell of origin without special staining.
◦ General Characteristics: Morphologically heterogeneous; difficult to distinguish cell of origin without special staining.
◦ Fibrosarcomas: Most common STS in cats; highly invasive; ~10% metastatic rate in dogs.
◦ Fibrosarcomas: Most common STS in cats; highly invasive; ~10% metastatic rate in dogs.
◦ Feline Injection Site Sarcomas (ISS): Extremely aggressive; associated with adjuvanted vaccines (Rabies/FeLV) and long-acting corticosteroids.
◦ Feline Injection Site Sarcomas (ISS): Extremely aggressive; associated with adjuvanted vaccines (Rabies/FeLV) and long-acting corticosteroids.
◦ Fibromatosis: Aggressive, infiltrative but non-metastatic; common on dog heads.
◦ Fibromatosis: Aggressive, infiltrative but non-metastatic; common on dog heads.
• Fibrohistiocytic Tumors:
• Fibrohistiocytic Tumors:
◦ Canine Fibrous Histiocytoma: Generally a granulomatous inflammatory response rather than true neoplasia.
◦ Canine Fibrous Histiocytoma: Generally a granulomatous inflammatory response rather than true neoplasia.
◦ Malignant Fibrous Histiocytoma: Locally invasive sarcomas of intermediate malignancy.
◦ Malignant Fibrous Histiocytoma: Locally invasive sarcomas of intermediate malignancy.
Specialized Mesenchymal & Neural Tumors
Specialized Mesenchymal & Neural Tumors
• Peripheral Nerve Sheath Tumors:
• Peripheral Nerve Sheath Tumors:
◦ Amputation Neuromas: Non-neoplastic; common after tail docking or equine neurectomy.
◦ Amputation Neuromas: Non-neoplastic; common after tail docking or equine neurectomy.
◦ Neurofibromas/Neurofibrosarcomas: Arise from Schwann cells; usually locally infiltrative and non-metastatic.
◦ Neurofibromas/Neurofibrosarcomas: Arise from Schwann cells; usually locally infiltrative and non-metastatic.
• Adipose Tissue Tumors:
• Adipose Tissue Tumors:
◦ Lipomas: Benign; common in obese female dogs (Dobermans, Labs).
◦ Lipomas: Benign; common in obese female dogs (Dobermans, Labs).
◦ Infiltrative Lipomas: Intermediate malignancy; dissect along fascial planes and muscle bundles.
◦ Infiltrative Lipomas: Intermediate malignancy; dissect along fascial planes and muscle bundles.
◦ Liposarcomas: Rare; low metastatic potential but often pseudoencapsulated.
◦ Liposarcomas: Rare; low metastatic potential but often pseudoencapsulated.
• Vascular Tumors:
• Vascular Tumors:
◦ Hemangiomas: Benign blood vessel proliferations; appear as red-black nodules.
◦ Hemangiomas: Benign blood vessel proliferations; appear as red-black nodules.
◦ Hemangiopericytomas: Common in older dogs (Siberian Huskies, German Shepherds); multi-lobulated lesions on distal extremities.
◦ Hemangiopericytomas: Common in older dogs (Siberian Huskies, German Shepherds); multi-lobulated lesions on distal extremities.
◦ Angiosarcomas (Hemangiosarcomas): Highly aggressive; Solar-induced form common in short-haired, light-skinned dogs (Whippets, White Boxers, Pit Bulls).
◦ Angiosarcomas (Hemangiosarcomas): Highly aggressive; Solar-induced form common in short-haired, light-skinned dogs (Whippets, White Boxers, Pit Bulls).
• Cutaneous Smooth Muscle Tumors:
• Cutaneous Smooth Muscle Tumors:
◦ Leiomyomas (Benign) & Leiomyosarcomas (Malignant): Rare; treated with surgery and potentially vincristine.
◦ Leiomyomas (Benign) & Leiomyosarcomas (Malignant): Rare; treated with surgery and potentially vincristine.
Epithelial & Adnexal Tumors
Epithelial & Adnexal Tumors
• Basal Cell Neoplasms: Benign (pigmented in cats) vs. Malignant (locally invasive basal cell carcinoma).
• Basal Cell Neoplasms: Benign (pigmented in cats) vs. Malignant (locally invasive basal cell carcinoma).
• Squamous Cell Carcinoma (SCC): Solar-induced; subungual form in dogs can invade bone.
• Squamous Cell Carcinoma (SCC): Solar-induced; subungual form in dogs can invade bone.
• Hair Follicle Tumors: Trichoepitheliomas (cystic) and Pilomatricomas (malignant forms metastasize to lungs).
• Hair Follicle Tumors: Trichoepitheliomas (cystic) and Pilomatricomas (malignant forms metastasize to lungs).
• Glandular Tumors:
• Glandular Tumors:
◦ Anal Sac Adenocarcinoma: Highly aggressive; produces PTHrP causing hypercalcemia.
◦ Anal Sac Adenocarcinoma: Highly aggressive; produces PTHrP causing hypercalcemia.
◦ Hepatoid Gland Tumors: Benign adenomas in males are usually androgen-dependent (castration responsive).
◦ Hepatoid Gland Tumors: Benign adenomas in males are usually androgen-dependent (castration responsive).
Round Cell & Melanocytic Tumors
Round Cell & Melanocytic Tumors
• Mast Cell Tumors (MCT): Most common malignant dog skin tumor; graded to predict survival; histamine release can cause GI ulcers.
• Mast Cell Tumors (MCT): Most common malignant dog skin tumor; graded to predict survival; histamine release can cause GI ulcers.
• Lymphocytic:
• Lymphocytic:
◦ Plasmacytomas: Usually benign nodules on ears/head.
◦ Plasmacytomas: Usually benign nodules on ears/head.
◦ Lymphosarcoma: Epitheliotropic (patch-to-tumor progression) or Nonepitheliotropic (systemic).
◦ Lymphosarcoma: Epitheliotropic (patch-to-tumor progression) or Nonepitheliotropic (systemic).
• Histiocytic: Cutaneous Histiocytomas ("button tumors") often resolve spontaneously in young dogs.
• Histiocytic: Cutaneous Histiocytomas ("button tumors") often resolve spontaneously in young dogs.
• Melanocytic:
• Melanocytic:
◦ Melanocytoma: Benign.
◦ Melanocytoma: Benign.
◦ Malignant Melanoma: Common at mucocutaneous junctions; 80% of older gray horses affected at the tail base.
◦ Malignant Melanoma: Common at mucocutaneous junctions; 80% of older gray horses affected at the tail base.
Metastatic & Viral Lesions
Metastatic & Viral Lesions
• Metastatic Tumors: Unusual; Feline Lung-Digit Syndrome involves primary lung tumors spreading to the feet.
• Metastatic Tumors: Unusual; Feline Lung-Digit Syndrome involves primary lung tumors spreading to the feet.
• Viral Papillomas (Warts): Generally self-limiting and regressive; caused by species-specific DNA viruses.
• Viral Papillomas (Warts): Generally self-limiting and regressive; caused by species-specific DNA viruses.
Page updated
Google Sites
Report abuse