Mast Cell Tumour + Transitional Cell Carcinoma Flashcards
What are canine mast cell tumours?
- Most commonly diagnosed skin tumour in the dog (16-21%).
- Other sites = subcutaneous tissue, conjunctiva, oral mucosa, GIT.
*Very variable behaviour - Various treatments available which need to be tailored to each case
What is presentation of MCTs? risk factors?
- Unknown aetiology
- Any age and no sex predilection
- Breed predispositions e.g. Boxer, Boston terrier.
- Sharpei get high grade MCTs
- Variable biological behaviour
- Invasiveness of primary tumour
- Metastatic rate 10->90%
- local lymph nodes
- spleen and liver
- Cutaneous masses of variable appearance - erythema, oedema, pruritus, haemorrhage
How are MCTs diagnosed?
- FNA of the mass = Usually diagnostic (92-96%), Round cells, Characteristic purple granules
- Diff Quick usually fine - Occasionally need special stains (eg toluidine blue)
- For some poorly differentiated = biopsy +/- IHC required
What can be done to stage MCTs?
- Abdominal US - assess liver, spleen, LNs, (FNA)
- Thoracic radiography - lung metastasis, comorbidities
- Buffy coat - non-specific + greater in inflammatory disease (when spun bloods - WBCs)
- Bone marrow aspirates - rare unless extensive disease
- Biopsy - FNA inconclusive, pre-surgical to determine grade
What does prognosis of MCTs depend on?
Clinical:
* Location eg Nail bed, oral, muzzle, prepuce, perineum, mucocutaneous junction.
* Breed (Sharpei vs boxer)
* Appearance
* Systemic illness
* Recurrence
* Clinical staging (i.e. presence of metastatic disease)
Laboratorial:
* Tumour histological grade (Most important)
* Other =
- Ki67
- AGNORs
- C-kit mutation
- Kit staining pattern
What is the PATNAIK grading system?
- Most important prognostic factor - 3 grades
- Grade I / well differentiated tumours = Benign behaviour (<10% metastasise), Low recurrence rates, Unlikely to cause death (up to 7-12%)
- Grade II/ intermediate tumours = Variably metastatic (5-22% metastasise), Cause of death in 17-56% of patients, Nodal metastases associated with poorer prognosis in some studies but not in all
- Grade III/ poorly differentiated tumours = Highly metastatic (>80%), Likely to be cause of death
What is the KIUPEL grading system?
- 2 groups = low + high grade
- Median survival time
– less than 4 months for high-grade MCT
– more than 2 years for low-grade MCTs
What is treatment of MCTs?
- Multimodal Tx needed
Surgery = - Margins
- 3cm margins & 1 fascial plane
- 1-2cm lateral margins may be adequate for grade I and II tumours
- Histopathology - all excised masses; grade and margins
- Grade I and II - Potential to be curative
- Grade III - Still a role but not as sole modality
What occurs if incomplete margins after surgery?
- 23% incompletely excised grade II recur
- 5-11% completely excised recur
- ~25% cases re-excision of scar reveals no mast cells
What should be done after surgery?
- Radiotherapy - postop - incomplete excision / local nodal metastasis / gross disease - degranulation
- Chemotherapy - high grade +/or confirmed mets, residual microscopic disease (Vinblastine/prednisolone)
What is seen with Feline MCT?
Cutaneous form
* Second most common cutaneous tumour in the cat (20%)
* Cutaneous raised hairless masses. Easily diagnosed by cytology and rarely metastatic. Multiple tumours.
* Surgical excision is usually curative (even marginal).
Visceral forms
* Splenic: Most common differential for splenic disease. Clinical signs of systemic disease. Staging is recommended. Splenectomy is the treatment of choice even if involvement of other organs. Unclear role of chemotherapy.
* Intestinal: Third most common intestinal tumour. Signs of GI and systemic disease and palpable abdominal mass. Metastasis are common. Poor prognosis
Where do animals get transitional cell tumours? Can the metastasise, if so where?
- Urinary bladder - Trigone
- Urethra + prostate in males
- High metastatic rate
- Common mets to medial iliac lymph nodes + other organs - liver, spleen, bones
What are clinical presentation of Transitional cell tumours?
- Low urinary tract signs (haematuria, stranguria, pollakiuria).
- Occasionally signs related with bone metastasis (lameness) or renal dysfunction.
- Signs can be present for months as dog gets treated for “complicated UTIs”.
- Signs may improve with courses of antibiotics
How are TCTs diagnosed?
- Histopathological diagnosis although sometimes cytology very suggestive.
- Risk of seeding with FNA
- Traumatic catheterization/ prostatic wash
- Cystoscopy (mainly females)/ surgical biopsy
What can you use to stage TCTs?
** Haematology/ Biochemistry/Urine analysis (including culture) **
- May show neutrophilia, renal dysfunction, presence of UTI
- Rule out any other problems and suitability for subsequent therapies
** Abdominal ultrasound **
* Assess bladder wall, urethra, prostate and kidneys +/- metastasis in other organs.
* FNA.
**n T&A radiography **
* Lung metastasis uncommon
* Bone metastasis
