ONCOLOGY - Skin and Soft Tissue Tumours Flashcards
Which history questions should be asked when investigating skin and soft tissue lesions?
Has there been any recent injury or trauma?
When was the lesion first noticed?
What is the rate of growth of the lesion?
Is the lesion hot or painful?
Have there been any other clinical signs?
Which specific factors should you assess on clinical examination when investigating skin and soft tissue lesions?
Full thorough clinical examination
Anatomical site of the lesion
Depth of the lesion
Measure the lesion
Assess for ulceration of the lesion
Mobility of the lesion
Which anatomical sites are associated with more malignant tumours?
Mucocutaneous sites
Dorsum
Digits
How do you diagnose skin and soft tissue tumours?
Diagnostic imaging
Fine needle aspirate (FNA) and cytology
Biopsy and histopathology
What should you do if you suspect a skin or soft tissue tumour?
TNM tumour staging
What are the differential diagnoses for skin lesions other than skin neoplasia?
Hyperplastic conditions
Granulomatous conditions
Immune-mediated conditions
Developmental lesions
(T/F) Skin neoplasia usually has multiple lesions
FALSE. Skin neoplasia usually presents with solitary lesions
What are the differential diagnoses for multiple skin lesions?
Metastasis from another primary tumour
Primary cutaneous lymphoma
Disseminated mast cell tumours
Histiocytic skin conditions
What are the two possible underlying aetiologies for histiocytic conditions?
Immune mediated
Neoplastic
What are the two classifications of immune mediated histiocytic conditions?
Cutaneous histiocytosis
Systemic histiocytosis
What is the typical signalement for cutaneous histiocytosis?
Young dogs
Which dog breeds are predisposed to cutaneous histiocytosis?
Bernese Mountain dogs
Rottweilers
Flat Coated Retrievers
Golden Retrievers
How does cutaneous histiocytosis typically present grossly?
Cutaneous histiocytosis typically presents as diffuse, erythematous, nodular lesions
What are the classifications of neoplastic histiocytic skin conditions?
Cutaneous histiocytoma (benign)
Histiocytic sarcoma (malignant)
Haemophagocytic histiocytic sarcoma (malignant)
What is the typical signalement for a cutaneous histiocytoma?
Young dogs (less than 5 years old)
What are the possible anatomical locations for a cutanenous histiocytomas?
Head
Limbs
Feet
Trunk
What is the typical appearance of a cutaneous histiocytoma?
Cutaneous histiocytomas typically present as raised, alopecic, domed, rapidly growing lesions (rapidly growing but is still benign)
How do you treat cutaneous histiocytomas?
Cutaneous histiocytomas should spontaneously regress if left alone however can be removed by surgical excision
What are the subclassifications of histiocytic sarcomas?
Focal histiocytic sarcoma
Diffuse histiocytic sarcoma
Which dog breeds are predisposed to histiocytic sarcomas?
Bernese Mountain dogs
Rottweilers
Flat Coated Retrievers
Golden Retrievers
What are the three classifications of solitary skin tumours that are found in the epidermis?
Papilloma
Basal cell tumour
Squamous cell carcinoma
What is a papilloma?
A papilloma is a benign wart-like growth that is induced by papilloma virus
What is the typical signalement for papillomas?
Young dogs and cats
What is the most common anatomical location for papillomas?
Oral papilloma
How do you treat papillomas?
Papillomas should resolve spontaneoulsy
What are the differential diagnoses for papillomas in dogs?
Sebaceous hyperplasia/adenoma
However these are mainly seen in older dogs
What are fibropapillomas?
Fibropapillomas, also known as sarcoids, are benign wart-like growths seen in cats and are induced by bovine papilloma virus
What are the other terms used to describe basal cell tumours?
Trichoblastomas
Solid-cystic apocrine ductal adenoma
Which signalement typically presents with basal cell tumours?
Middle aged to old dogs and cats
How do basal cell tumours typically present grossly?
Basal cell tumours are typically benign, slow growing, solitary well circumscribed, raised/domed, maybe pigmented lesions
How do you treat basal cell tumours?
Wide local resection
What is the most common cause of squamous cell carcinomas?
Squamous cell carcinomas are usually caused by chronic exposure of unpigmented skin to UV light, resulting in solar dermatitis which progresses to an in situ carcinoma which progresses to an infiltrative squamous cell carcinoma
What is a Bowen’s in situ carcinoma (BISC)?
A Bowen’s in situ carcinoma (BISC) as a squamous cell carcinoma induced by papilloma virus infection
(T/F) Squamous cell carcinomas exhibit rapid lymphatic metastasis
FALSE. Squamous cell carcinomas are locally invasive and exhibit variable, often slow, lymphatic metastasis
What are the most common anatomical sites for a squamous cell carcinoma?
Ears
Nose planum
Digits
How do you treat squamous cell carcinomas of the ears?
Wide local excision which requires surgical removal of the ears
What are the main species differences between squamous cell carcinomas on the nasal planum?
In cats, squamous cell carcinomas on the nasal planum are induced by UV light, affect unpigmented skin and are less aggressive. In dogs, squamous cell carcinomas on the nasal planum are not induced by UV light, affect pigmented skin and are very invasive and aggressive
What are the treatment options for very superficial, early stage nasal planum squamous cell carcinoma in cats?
Radiotherapy
Brachytherapy
Photodynamic therapy
Electrochemotherapy
What is brachytherapy?
Brachytherapy is a form of radiation therapy where a sealed radiation source is placed inside or next to the area requiring treatment
What is photodynamic therapy?
Photodynamic therapy involves the injection of a photosensitising agent and the drug is absorpbed and selectively accumulates in neoplastic cells. After a certain amount of time, the affected area is exposed to a specific wavelength of light. The light activates the photosensitizer, which then produces reactive oxygen species which will damage the neoplastic cells
What is electrochemotherapy?
Electrochemotherapy is a treatment combining electrical pulses with chemotherapy drugs to enhance drug delivery to neoplastic cells
How do you treat nasal planum squamous cell carcinoma in dogs?
Wide local excision involving a nosectomy and radiotherapy
What are the three anatomical classifications of digit squamous cell carcinoma?
Remember tumours on the digits are very aggressive
Digital squamous cell carcinoma
Interdigital squamous cell carcinoma
Subungual squamous cell carcinoma
Which signalement typical presents with digit squamous cell carcinomas?
Black coated, large breed dogs
How do digit squamous cell carcinomas typically present grossly?
Digital squamous cell carcinomas typically present as ulcerative, haemorrhagic lesions and can present with lameness due to local bone infiltration and destruction
How do you treat digit squamous cell carcinomas?
Digit amputation and radiotherapy
What is feline lung digit syndrome?
Feline lung digit syndrome is a pulmonary adenocarcinoma which clinically presents as metastatic lesions of the digits in cats
What are the differential dignoses for tumours on the digits other than squamous cell carcinoma?
Mast cell tumour
Melanoma
Soft tissue sarcoma
Osteosarcoma
What are the classifications of solitary skin tumours that are found in the dermis?
Adnexal tumours
What are the classifications of adnexal tumours?
Sebaceous gland tumours
Sweat gland tumours
Hair follicle tumours
Meibomian gland tumours
What are the subclassifications of sebaceous gland tumours?
Sebaceous gland hyperplasia/adenoma
Sebaceous gland carcinoma
What is the most common skin tumour seen in older dogs?
Sebaceous gland hyperplasia/adenoma
Which dog breeds are predisposed to sebaceous gland hyperplasia/adenoma?
Cocker Spaniel
Poodle
What are the subclassifications of sweat gland tumours?
Sweat gland carcinoma
What are the subclassifications of hair follicle tumours?
Pilomatricoma
Trichoepithelioma
Trichoblastoma
Maltricial carcinoma
What is a pilomatricoma?
A pilomatricoma is a benign adnexal tumour arising from the hair matrix cells
What is a maltricial carcinoma?
A maltricial carcinoma is a malignant adnexal tumour arising from the hair matrix cells
What is a perianal adenoma?
A parianal adenoma is a benign, hormone mediated tumour arising from the specialised sebaceous gland
What is the typical signalement for a perianal adenoma?
Old, intact male dogs
What is the typical appearance of a perianal adenoma grossly?
A perianal adenoma typically presents as a solitary, button-like, alopecic, domes lesion at the perineal skin or the anal sphincter. Perianal adenomas can begin to increase in size and ulcerate (however this is usually a sign of malignancy)
How do you treat a perianal adenoma?
A perianal adenoma is a benign, hormone driven tumour and thus will usually regress with castration, however can also undergo wide local excision
How do you treat a perianal carcinoma?
Perianal carcinomas are malignant and thus not hormonally mediated and this castration cannot be used to treat these tumours. They require wide local excision or radiotherapy or more marginal excision with adjunctive chemotherapy
How do you differentiate perianal carcinomas from anal sac adenocarcinoma?
Perianal carcinomas present more grossly on the perineal skin or anal sphincter, whereas anal sac adenocarcinomas are usually felt on rectal palpation or present as perineal swellings
(T/F) Melanoma is a common tumour in small animals
FALSE. Melanoma is a relatively rare tumour in small animals
(T/F) Melanomas are usually benign in small animals
TRUE.
Which anatomical signs for malignant melanomas are typically more aggressive?
Oral
Anal
Digits
How do you treat malignant melanomas?
Wide local excision or radiotherapy for the primary tumour
Chemotherapy for the metastasis
What is the typical signalement for cutaneous mast cell tumours?
Middle aged to old dogs, occasionally seen in puppies
Can also be seen in cats but not as commonly
Which dog breeds are predisposed to cutaneous mast cell tumours?
Boxers
Labradors
Golden Retrievers
Staffordshire Bull Terriers
Boston Terriers
Weimeraner
Pugs
Which dog breeds often present with multiple, unrelated cutaneous mast cell tumours?
Boxer
Labrador
Golden Retriever
Very important to do biospy and histology on the lesions to ensure they are truly unrelated and not metastasis
What is the typical appearance of cutaneous mast cell tumours grossly?
Cutaneous mast cell tumours have a very variable gross appearance as well as behaviour and degrees of metastasis
How do mast cell tumours cause paraneoplastic syndromes?
Mast cell tumours can cause local or systemic paraneoplastic effects through spontaneous or traumatic degranulation
What is contained within mast cell granules?
Histamine
Heparin
Vasoactive amines
What are the local paraneoplastic effects of mast cell tumours?
Erythema
Swelling
Wheals (also known as Darier’s sign)
These lesions can fluctuate in size
Which mast cell tumour grade is typically associated with local paraneoplastic effects?
Low grade mast cell tumours are typically associated with local paraneoplastic effects
What are the systemic paraneoplastic effects of mast cell tumours?
Gastric ulceration
Vomiting
Anorexia
Hypotension
Coagulation abnormalities
Delayed wound healing
How do mast cell tumours cause gastric ulceration??
Mast cell tumours can degranulate and release histamine which will bind to H2 receptors on the parietal cells to stimulate excessive gastric acid production resulting in gastric ulceration
What are the key features of systemic paraneoplastic syndrome secondary to mast cell tumours on biochemistry?
Hyperhistaminaemia
Hypogastrinaemia (due to negative feedback loop due to excessive gastric acid production)
How do you manage systemic paraneoplastic syndrome due to mast cell tumours?
Intravenous fluids
Gastroprotectants (H2 blockers, proton pump inhibitors and sucralfate)
Treat the mast cell tumour
Which mast cell tumour grade is typically associated with systemic paraneoplastic effects?
High grade mast cell tumours are typically associated with systemic paraneoplastic effects
How do you diagnose mast cell tumours?
Fine needle aspirate (FNA) and cytology
Biospy and histopathology
What should you do prior to incising a mast cell tumour?
Pretreament with antihistamines
How do you clinically stage mast cell tumours?
Clinical stage 0: Incompletely excised mast cell tumour from the dermis with no lymph node involvement
Clinical stage I: Single tumour in the dermis with no lymph node involvement
Clinical stage II: Single tumour in the dermis with lymph node involvement
Clinical stage III: Multiple dermal tumours or large infiltrating tumours ± lymph node involvement
Clinical stage IV: Any tumour with distant metastasis, blood or bone marrow involvement
Each stage can be subclassified as a) if there are systemic clinical signs and b) if there are no systemic clinical signs
How do you treat clinical stage I mast cell tumours?
Wide local excision
Which other treatment options are available for a clinical stage I mast cell tumour if wide local excision is not feasible?
Marginal excision and radiotherapy
Radiotherapy alone
How do you treat clinical stage II mast cell tumours?
Wide local excision for the primary tumour
Lymph node excision
Adjunctive chemotherapy
Which other treatment options are available for a clinical stage II mast cell tumour if wide local excision is not feasible?
Marginal excision and radiotherapy
Radiotherapy alone
How do you determine if a clinical stage II mast cell tumour requires adjunctive chemotherapy?
Histological grading
How do you treat low grade/grade I and low grade/grade II mast cell tumours?
Wide local excision should have been sufficient to treat this tumour grade if the histological margins are complete. If the histological margins are incomplete, consider further surgery or radiotherapy. If radiotherapy is unavailable, consider chemotherapy if there are any signs of malignancy
How do you treat high grade/grade II and high grade/grade III mast cell tumours?
Cytoreductive surgery using wide local or radical excision is required for the primary tumour with radiotherapy if good surgical margins were not achieved. Adjunctive chemotherapy is always indicated with these tumour grades
Which protocols can be used as adjunctive chemotherapy for mast cell tumours?
Vinblastine and Prednisolone
Single agent lomustine
Describe the vinblastine and prednisolone chemotherapy protocol for mast cell tumours
IV injections of vinblastine once a week for 4 doses, then every 2 weeks for the subsequent 4 doses
Daily oral prednisolone for 2 weeks followed by halving the dose and giving daily oral prednisone for 10 weeks
Describe the lomustine chemotherapy protocol for mast cell tumours
Oral lomustine every 3 weeks for 4 - 6 doses
Which chemotherapy drugs are licensed as a sole agent for unresectable gross mast cell tumours?
Mastinib
Toceranib
Which grading systems are used in combination to histologically grade cutaenous mast cell tumours?
Patnaik grading system
Kiupel grading system
Which other factors can be assessed to grade mast cell tumours?
Mitotic index
Ki67 staining
AgNOR (silver) staining
cKIT marker
Which mitotic index can indicate a higher degree of malignancy in cutaneous mast cell tumours?
A mititic index of over 5 mitoses over 10 high power views indicates a higher degree of malignancy and worse prognosis for a cutaneous mast cell tumour
Which mitotic index can indicate a higher degree of malignancy in subcutaneous mast cell tumours?
A mititic index of over 4 mitoses over 10 high power views indicates a higher degree of malignancy and worse prognosis for a subcutaneous mast cell tumour
What is Ki67 staining?
Ki67 is a nuclear stain which stains the nucleus of cells within the cell cycle. The higher the percentage of Ki67 staining, the higher degree of cellular proliferation
Which Ki67 staining percentage indicates a higher degree of malignancy in cutaneous mast cell tumours?
Ki67 staining of over 1.8% per total mast cell count within the field indicates a higher degree of malignancy and a worse prognosis for a cutaneous mast cell tumour
What is AgNOR (silver) staining?
AgNOR staining is a nuclear silver stain. The higher the percentage of AgNOR staining, the higher degree of cellular proliferation
What are cKIT markers?
cKIT markers are cell surface proteins that are a type of tyrosine kinase receptor seen on the surface of mast cells, and is important in the regulation of cell growth, differentiation, survival and proliferation
How can cKIT markers be used to determine prognosis for mast cell tumours?
cKIT mutations are common in high grade mast cell tumors and are linked to a poor prognosis, however are particularly responsive to tyrosine kinase inhibitors (TKIs). These mutations can be detected by PCR. The location within the cell as to which the cKIT marker is expressed is also indicative of prognosis
What is indicated by the membranous expression of the cKIT marker?
The membranous expression of the cKIT marker is generally seen in normal mast cells or low grade mast cell tumours, and thus have a better prognosis
What is indicated by the focal cytoplasmic expression of the cKIT marker?
The focal cytoplasmic expression of the cKIT marker is associated with a worse prognosis
What is indicated by the systemic cytoplasmic expression of the cKIT marker?
The systemic cytoplastic expression of the cKIT marker is generally associated with high grade mast cell tumours and thus has an even worse prognosis
What is the typical signalement for feline cutaneous mast cell tumours?
Older cats (approximately 11 years old)
Which cat breed is predisposed to cutaneous mast cell tumours?
Siamese
How do you treat cutaneous mast cell tumours in cats?
Typically, cutaneous mast cell tumours in cats are solitary and benign and this can be treated with wide local excision
What are soft tissue sarcomas?
Soft tissue sarcomas are a group of malignant tumours which arise from the mesenchymal cells typically within the subcutaneous tissues. Soft tissue sarcomas are typically locally infiltrative and invasive and can metastasise
Which route of metastasis is typically utilised by soft tissue sarcomas?
Haematogenous
Thus there is rarely lymph node involvement
How do you treat soft tissue sarcomas?
Radical excision for the primary tumour (or a more marginal excision with radiotherapy if this isn’t possible)
Chemotherapy for metastasis
Why do soft tissue sarcomas require radical excision?
Soft tissue sarcomas form a pseudocapsule through compressing the cells in the outer zone of the tumour. This is not a true capsule enclosing the tumour and thus there are neoplastic cells outside the pseudocapsule, so the tumour will require radical excision to remove the neoplastic cells
When is chemotherapy indicated in the treatment of soft tissue sarcoma?
Chemotherapy is indictaed as adjunctive therapy for high grade soft tissue sarcomas
Which chemotherapy protocol is typically used for soft tissue sarcomas?
Sole agent doxorubicin
What are feline injection site sarcomas?
Feline injection site sarcomas are very infiltrative and high grade soft tissue sarcoma that develop at or near the site of an injection in cats, most commonly after vaccination
How do you treat feline injection site sarcomas?
Radical excision with adjunctive radiotherapy for primary tumour (important to do advanced imaging to ensure complete tumour removal)
Chemotherapy for metastasis
What are haemangiosarcomas?
Haemangiosarcomas are highly aggressiven malignant tumours originating from the endothelial cells
WHat is the typical signalement for haemangiosarcomas?
Older cats ands dogs
Which dog breeds are predisposed to haemangiosarcomas?
German Shepherd
Labrador
Golden Retriever
What are the potential anatomical sites for haemangiosarcomas?
Spleen
Right atrium
Pericardium
Muscle
Skin
What are the potential clinical presentations of haemangiosarcomas?
Clinical signs of a splenic rupture
Cardiovascular signs
Disseminated intravascular coagulation (DIC)
Superficial soft tissue mass
What are the clinical signs of a splenic rupture?
Haemorrhagic anaemia
Collapse
Hypovolaemic shock
What are the main differentials for splenic masses?
Splenic haemangiosarcoma
Splenic haemangioma
Splenic haematoma
How do you treat a haemangiosarcomas?
Radical surgical excision (may require a splenectomy, pericardectomy, amputation etc) for primary tumour
Chemotherapy for metastasis
Which chemotherapy protocols are typically used for haemangiosarcomas?
Sole agent doxorubicin
Metronomic cyclophosphamide and NSAIDs
What is the prognosis for a splenic haemangiosarcoma with surgery alone?
1 - 3 months
What is the prognosis for a splenic haemangiosarcoma with surgery and chemotherapy?
5 - 7 months
What is the prognosis for a cardiac haemangiosarcoma with no treatment?
12 days
What is the prognosis for a cardiac haemangiosarcoma with chemotherapy?
3 - 4 months
What is the prognosis for an intramuscular haemangiosarcoma with chemotherapy?
6 - 9 months
What are the two classifications of skin haemangiosarcomas?
Dermal haemangiosarcoma
Subcutaenous haemangiosarcoma
What is the prognosis for a dermal haemangiosarcoma with surgery?
26 - 33 months
What is the prognosis for a subcutaneous haemangiosarcoma with surgery?
7 - 10 months
