Small animal skin masses workshop Flashcards
5yo FN Labrador retriever
1cm erythematous nodule on dorsal aspect of radius
Little changed since first seen 2 weeks previously, though does appear to cause some irritation
What is the D/d list?
Penetrating wound causing infection/inflammation / cellulitis
Insect bite with inflammation
Mast cell tumour (MCT)
Histiocytoma
Label the FNA cytology
5yo FN Labrador retriever
1cm erythematous nodule on dorsal aspect of radius
Little changed since first seen 2 weeks previously, though does appear to cause some irritation
Based on lesion & cytology what is the diagnosis? What would you do next?
MCT
- Metastatic potential so screen local lymph node +/- liver & spleen
- Wide excision required but difficult at this site – consult oncologist
- Histology would be required for grading
3 yo FN Miniature Poodle, recently neutered, when no abnormalities were detected
1.5cm diameter firm, painless interscapular nodule has subsequently developed
What is the D/d list?
Injection reaction
Microchip reaction
Tumour eg spindle cell tumour, MCT
Cyst
Label the FNA cytology
Label the FNA cytology
3 yo FN Miniature Poodle, recently neutered, when no abnormalities were detected
1.5cm diameter firm, painless interscapular nodule has subsequently developed
Based on lesion & cytology what is the diagnosis? What would you do next?
Mixed inflammation within adipose tissue = panniculitis
No evidence of infection (but cannot preclude)
Classical appearance of injection reaction
Usually resolves spontaneously
9yo MN Staffordshire Bull Terrier
3cm diameter well-defined soft mass on medial thigh. Enlarged slightly over past 6 months.
What is D/d list?
Lipoma
Benign cyst
MCT
Low grade other neoplasm, e.g.
- spindle cell tumour
- adnexal tumour
Label the FNA cytology
9yo MN Staffordshire Bull Terrier
3cm diameter well-defined soft mass on medial thigh. Enlarged slightly over past 6 months.
Based on lesion & cytology what is the diagnosis? What would you do next?
Lipoma
NB subcutaneous fat appears identical
If fat is aspirated but lesion looks aggressive, may have unrepresentative sample - repeat aspirate if in doubt
12yo MN DSH cat
Ill-defined swelling on left dorsal scapular region, noted first 3d ago
What is the D/d list?
Abscess / cellulitis
Sarcoma eg haemangiosarcoma, osteosarcoma, ?injection site sarcoma
Mast cell tumour
Label the FNA cytology
12yo MN DSH cat
Ill-defined swelling on left dorsal scapular region, noted first 3d ago
Based on lesion & cytology what is the diagnosis?
Septic inflammation
Many neutrophils seen
- Don’t appear degenerate but there are intracellular bacteria indicating infection
Consistent with abscess/area of cellulitis
- eg due to a cat bite
11yo ME Labrador
Irregular, ill-defined firm nodule, 6cm diameter, over right caudal radius. Noted to have increased in size over past month
What is D/d list?
Inflammatory mass
Neoplasm, esp spindle cell tumour
Label the FNA cytology
11yo ME Labrador
Irregular, ill-defined firm nodule, 6cm diameter, over right caudal radius. Noted to have increased in size over past month
Based on lesion & cytology what is the diagnosis? What would you do next?
FNA consistent with spindle cell (mesenchymal) tumour
Biopsy required for histopathological diagnosis:
- Vascular wall tumour (haemangiopericytoma) confirmed on incisional biopsy
- Locally invasive but infrequently metastasise
- Complete surgical excision if possible +/-radiotherapy if needed
