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Diagnostics & Staging
Stacy Santoro Binstock, DVM, DACVIM (Oncology)

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The Hallmarks of Cancer:
- Self-sufficiency in growth signals
- Evading apoptosis
- Insensitivity to antigrowth signals
- Sustained angiogenesis
- Tissue invasion and metastasis
- Limitless replicative potential

Hanahan & Weinberg, Cell 2000.

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Diagnosis
- Cytology
Useful for round cell tumors
- Histopathology
Gold standard for solid tumors
- After the diagnosis is obtained... Now what?

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GRADING
- Degree of malignancy
- Predictive of biologic behavior
- Subjective
Reproducibility variable
Tumor heterogeneity
Looks different from area to area
Careful with incisional biopsy samples
GRADE: DESCRIPTION
GRADE1: Small, uniform cells, tightly packed
GRADE2: Varied cell sizes and shapes, loosely packed
GRADE3: Increased cell size and shape irregularity, less distinction between cells
GRADE4: Large, irregular, fused cells
GRADE5: Irregular, fused cells that have invaded surrounding connective tissue cells

Prostate.com

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GRADING
- Degree of differentiation
- Mitotic index
- Cellular/nuclear pleomorphism
- Necrosis
- Invasiveness
- Stromal reaction
- Nucleolar size and number
- Cellularity
- Lymphoid response

Staging: Progression or spread in the body,
Grading: Cell differentiation & Rate of growth - Microscopy

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HISTOLOGIC SIGNIFICANCE
- Mast cell tumor
- Lymphoma
- Soft tissue sarcoma
- Pulmonary carcinoma
- Synovial cell sarcoma
- Chondrosarcoma
- Fibrohistiocytic nodule of spleen
- Multilobular osteochondrosarcoma
- Mammary carcinoma

Animalcancersurgeon.com

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STAGING
- Tumor size / degree of invasion (T)
- Regional lymph node involvement (N)
- Distant metastasis (M)

vet.uga.edu

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T - tumor size
- Measure tumor
- Mammary carcinoma, melanoma
N - node
- Cytology highly correlated to histopathology
- Size alone not predictive
M - metastasis
- CXR
7-9 mm detectable
- AUS
- CT scan
1 mm detectable
More sensitive in large/giant breed dogs with OSA

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MELANOMA
Stage 1: Primary tum or <2cm diameter
Stage 2: Primary tumor 2-<4 cm diameter
Stage 3: >4cm diameter tumor AND/OR local lymph node metastasis
Stage 4: Distant metastasis of any site

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RADIOGRAPHS
- Good screening test
- Readily available
- Simple
- Low cost
- Best for bone lesions

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RADIOGRAPHS VS. CT
- Osteosarcoma [Eberle et al. Vet Comp One 2011 Jun]
5% radiographs
28% CT scan
Nodules on CT not associated with prognosis
Number prognostic
- Metasitatic neoplasia in dogs [Nemaniac et, JVIM 2006 JUN]
Single breath hold
9% of CT pulmonary nodules found on radiographs
Size threshold
1 mm – CT scan
7 - 9 mm CXR
CXR detects fails to detect ~90% of nodules identified on CT

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A dog with a tumor in her mouth. This was a plasma cell tumor.

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CT scan of a plasma cell tumor in the mouth of a dog.

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CT scan

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CT scan

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ULTRASOUND
- Internal architecture of organs
- Image inside of body cavities
- Superior in instances of effusion
- Useful for FNA
- Very sensitive, not specific
- Not ideal for bone lesions

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CYTOLOGY
- Easily accessible
- Low risk
- No need for anesthesia/sedation
- No processing required

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OBTAINING A GOOD SAMPLE
- Preparation
- Use smaller gauge needle
22g (25 if bloody)
- +/ - aspiration technique
- Gentle handling
- Thin smears
Monolayer easier to interpret
- Save unstained slides
- Review sample to assure adequate

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How to obtain a good cytology sample

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CLASSIFICATION
- Epithelial
- Mesenchymal
- Round
- Benign or malignant?

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EPITHELIAL TUMORS
- Carcinomas
- Cohesive
- Clusters of cells
- Round in appearance
- Intercellular junctions
- No extracellular matrix

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MESENCHYMAL TUMORS
- Sarcomas
- Individually exfoliating
- Extracellular matrix
- Exfoliate poorly
- Spindle - shaped
- Indistinct cytoplasmic borders
- May be reactive

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ROUND CELL TUMORS
- Discrete, individual cells
May appear clumped if thick sample
- Readily exfoliate
- Highly cellular sample(s)
- Round nuclei, distinct cytoplasmic
margins
- Mast cell tumors
- Plasma cell tumors
- Lymphoma
- Histiocytoma
- TVT
- Melanoma

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Indented nuclei
Vacuoles
Perinuclear clear zone

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MCT CYTOLOGY
Diff Quick
Wright stain

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CRITERIA OF MALIGNANCY
- Anisocytosis
- Anisokaryosis
- High N:C
- Multinucleation
- Mitotic figures
- Pleomorphism
- Coarse chromatin
- Nuclear molding
- Basophilic cytoplasm
- Macronuclei

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LIMITATIONS OF CYTOLOGY
- No grade
Mast cell tumor
Underestimates high grade tumors
- Margin evaluation not possible
- Lack of architecture
Small cell GI lymphoma in cats
- May not be able to differentiate tumor from inflammation
Soft tissue sarcoma
Mammary carcinoma (dog)

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IMMUNOPHENOTPYE
- Lymphoma
Dogs
- B vs. T cell phenotype is prognostic
Some clinicians alter chemotherapy

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FLOW CYTOMETRY VS. PARR
- Which test do I submit?
- What are the clinical signs?
Enlarged lymph nodes
Lymphocytosis
Cavitary effusion
- Fluid vs. tissue
- Which question am I trying to answer?
Is this lymphoma
What type of lymphoma
- What kind of sample do I have?
Blood vs. tissue
Fresh
Low cellularity

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Species
Clinical signs
Sample
Cytology
Best test

Dog/Cat
Lymphocytosis
Blood
Small mature or large lymphocytes
Flow

Dog/Cat
Lymphadenopathy
Lymph node
Lymphoma (small or large)
Flow (B v. T)

Dog/Cat
Lymphadenopathy
Lymph node
Mixed or reactive, rare suspicious cells
PARR

Dog/Cat
Cavitary effusion
Thoracic/abdominal fluid
Abnormal large or small lymphoid cells
Flow

Dog/Cat
Mediastinal mass
Mass
Lymphoma or thymoma
Flow

Dog/Cat
Cavitary effusion
Thoracic/abdominalFluid
Rare lymphoid cell
PARR

Dog/Cat
Leukopenia
Bone marrow
No neoplastic cells
PARR

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MAST CELL TUMOR PANEL
- Not for all tumors
- Helps to tease out potentially more aggressive MCTs
SQ MCT
- Useful for tumors with biopsy that does not fit clinical picture
Rapidly growing
Concerning location
Muzzle, perineal, aural, etc
Incompletely excised
- Submit formalin fixed tissue or FNA(cytology for c-kit OCR only)
- Use to guide therapy

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MCT PANEL
- Grade
- Proliferation indices
AgNOR , Ki67, PCNA
- C - kit
PCR for ITD
Exon 11
20 -30% of cases
Exon 8
2 - 5%
- IHC
Increased intracytoplasmic labeling
Loss of membrane associated labeling

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Considerations for inclusion of systemic therapy in treatment of dogs with canine cutaneous mast cell tumors
Grading
Staging
Highgrade
Low grade AND Negative staging
Positive staging
Positive staging
Evaluate proliferation
indices
PCR for activating c-kit mutation in exon 11
and IHC for KIT
High proliferation
Indices
Low proliferation indices AND No c-Kit mutation AND
KIT pattern 1
Demonstration of c-Kit mutation OR KIT pattern 2 or 3
No indication for further treatment
Systemic therapy should be considered

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Case Studies

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- Jack
- 11 yr old MC Cocker Spaniel
- Presented for evaluation of thyroid carcinoma
- 0.6 cm lump associated with nipple
Serosanguinous discharge

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Cytology

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- White Feet
- 9 yr old MC DSH
- 4 weeks history of vomiting, weight loss
- Abdominal mass palpated
Confirmed on AUS

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Cytology

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- Mac
- 10 yr old MC Lab
- Presented for decreased appetite, bad breath, mass in mouth
- Staging tests
CXR
Submandibular LN cytology
+/ - CT scan

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Cytology

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- Vita
- 9 yr FS Great Dane
- Lame right forelimb
- Minimal to no swelling
- Painful to touch

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Cytology

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- Jake
- 13 yr old MC DSH
- Recent onset anorexia, weight
- Ascites on PE
- Fluid cytology

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Cytology

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- Peter
- 6 yr MC mixed breed dog
- 3 cm moveable cutaneous
mass on right lateral thigh

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Cytology

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- Kenny
- 4 yr MC DMH
- Indoor/outdoor
- FeLV /FIV
- Fever, weight loss, lethargy, oral ulceration/mass

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Cytology

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- Rick
- 11 yr old MC German Shep X
- Presented for bleeding from the mouth, painful/
reluctant to eat, facial swelling, suspect mass
- ~3 cm ulcerated, necrotic mass on caudal R maxilla on PE

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Cytology

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QUESTIONS?