Mesenchymal Neoplasms Flashcards
What are the characteristics of mesenchymal cells?
variable exfoliation
indistinct, wispy cytoplasmic borders
spindle shaped, fusiform, stellate cells
cell individually arranged
more oval shaped nuclei than epithelial cells
Tissue of origin?
Benign or malignant?
Tumor type?
mesenchymal
malignant
Leiomyosarcoma
Which mesenchymal tumors may need histopathology to determine biological behavior?
Muscle tumors= Leiomyoma/sarcoma & myxoma/sarcoma
Cartilagenous tumors= chondroma/sarcoma
Via which route do mesenchymal tumors typically metastasize?
hematogenous routes
Describe the characteristics of malignancy in this sample? What general classification would this tumor be?
Anisokaryosis, mitotic figures, open chromatin, multiple nucleoli
Sarcoma
Tumor type?
Benign or malignant?
mesenchymal- lipoma
benign
An owner reports that she thinks a previously diagnosed lipoma has become cancerous and spread to the other areas of the dog’s ventrum. Is this a possibility?
No, liposarcomas do not arise from malignant transformations of lipomas
If you suspect that around an surgery scar there is an area of scar tissue/reactive fibroplasia, what should you do to confirm?
Histopathology
What is the most common cutaneous tumor of horses?
sarcoid
A firm, SQ mass is palpated on the hind end of a horse. On cytology of the mass, it appears mesenchymal. What are the top three differentials? How would you confirm?
sarcoid
Granulation tissue
fibroma
Perform histopathology to confirm tumor and biologic behavior
What four ST sarcomas do we typically all treat the same?
perivascular wall tumor
fibrosarcoma
myxosarcoma
peripheral nerve sheath tumor
Describe the characteristics of perivascular wall tumors.
High exfoliation
very vascular
multinucleated cells with peripheral nuclei (crown cells)***
very wispy cytoplasm and anaplastic cells
small punctate vacuoles
1-2 nucleoli
Tumor type?
mesenchymal, perivascular wall tumor
Tumor type
Soft tissue sarcoma
Tumor type?
ST sarcoma
Where are perivascular wall tumors commonly found?
on the extremities, especially the lateral surface
When is a biopsy for a mass from a vaccination warranted?
present 3 months after vaccination
>2 cm in diameter
increasing in size 1 month after vaccination
What are the characteristics of fibrosarcomas?
low exfoliation
individual arranged cells
pink eosinophilic matrix (collagen)
absence of inflammation
What comparative measure can be used to determine if a nucleus is enlarged?
compare to the size of a RBC
T/F Fibrosarcomas metastasize quickly.
FALSE
What are the characteristics of hemangiosarcomas on cytology? In which sites do we typically see these tumors?
variable exfoliation (hemodilute often)
large, typical cells
pale blue cytoplasm with clear vacuoles
Sites: spleen, liver, R-atrium, retroperitoneal space, bone, dermal (derived from mets most often)
Tumor type?
Benign or malignant?
Mesenchymal, hemangiosarcoma
[pale blue cytoplasm, cytoplasmic vacoules]
malignant
What are the site predilections for synovial cell sarcomas?
elbow, stifle, shoulder
Which tumor is hard to differentiate from synovial cell sarcoma on histo and cyto? (special stains needed)
Histiocytic sarcoma
synovial cell sarcomas are locally invasive and metastasize in 25% of reported cases. T/F
True
What are the features of synovial cell sarcomas?
granular eosinophilic background (mucin)
Dual population of anaplastic cells:
- oval with eccentrically placed nuclei
- spindle shaped
Name the three types of tumors that can affect the joints? What are their site/breed predilections?
- Synovial cell sarcoma- elbow, stifle, shoulder
- Histiocytic sarcoma- stifle, Rottweiler
- Synovial myxoma-stifle, Doberman
Tumor type?
Synovial cell tumor
(eosinophilic background, two aplastic cell populations)
What are the characteristics of osteosarcomas?
May appear as round cell tumors
Eccentric nuclei
Large, oval - spindle shaped cells (individual)
Dense, amorphous pink material (osteoid***)
variable, distinct cytoplasmic borders
muti-nucleated giant cells (osteoclasts)
What is the most common site for osteosarcoma in the cat?
femur
What are the sites common for osteosarcoma in a dog?
metaphyseal region
“away from the elbow, towards the knee”
- proximal humerus
- distal radius & ulna
- proximal tibia
- distal femur
Tumor type?
Osteosarcoma
(osteoid in the cells pink granular material is the give away)
Does osteosarcoma have a better prognosis in the cat or dog? Axial or appendicular skeleton?
cat
axial skeleton
What is the first diagnostic that should be performed on a dog with suspected osteosarcoma on the appendicular skeleton?
thoracic radiographs
