1. 5th Year Cytopathology
Tutorial
All content from Steven Kopp – UQ
Edited and labelled for personal study
purposes.

2. 8 year old Lab with Skin Mass

3. 8 year old Lab with Skin Mass
• Red, inflamed
• History questions
– How quickly has it come up?
• Rapidity of growth indicates haematoma, abscess, inflammatory
wheals
– Are there more than 1?
– Signalment of animal
• Steps to take
– PALPATION: solid/fluctuant, attached to underlying tissue, mobility,
warmth
– FNA: minor surgical procedure – needs to be sterile

5. Plasma Cell Eosinophil
Macrophage
Mast cells – Large
round, ovoid
nuclei.
Moderate
cytoplasm, purple
Amorphous
granules
Debris
Predominantly 1 cell type: NEOPLASIA

6. Neoplasia

7. Round Cell Neoplasms

8. Back to the Skin Lump
• Purple granules (Mast Cell) until obscure nucleus
• Eosinophils present bcos attracted to mast cell
degranulation
• Mast cells rarely gather in 1 area – if they do, they
are proliferating
• Neoplastic Round cell Tumour – MAST CELL TUMOUR

9. Skin Lump 2
Ulcerated, well circumscribed.

11. Wright’s Stain
Mainly histiocytes –
pale grey cytoplasm,
Large,
bubblegum pink, loose
ovoid, ofted
chromatin
indented,
eccentrically
located
nuclei
Lymphocytes
& Plasma
Cells
Starburst
mitotic
figure

12. Histiocytoma
• Neoplastic: monomorphic population
• Histiocytoma (Canine Cutaneous Histiocytoma)
– Benign
– Histiocytes: pale grey cytoplasm, bubblegum pink, loose
chromatin

13. Skin Lump 3
Mobiile, fistulous tracts

14. Toxic
Change
Neutrophils

15. Skin Lump
Macrophage
Intracytoplasmic
rods
Neutrophils

16. Inflammatory Mass
• Inflammation
– Neutrophilic (suppurative/purulent)
– Eosinophilic
– Granulomatous (macrophages – wall like structure)
– Lymphocytic
– Lymphoplasmacytic
• Toxic change: most probably septic (infection)
• Next step: culture & sensitivity

17. Skin Lesion

18. Cryptococcus
– have halo
Macrophage
Macrophages gobbling up
cell – GRANULOMATOUS
INFLAMMATION

19. • Well differentiated, foamy cytoplasm with small
nucleus  MACROPHAGES
• Thick gel-like capsule, not staining (stains with indian
ink), have budding base and halo  CRYPTOCOCCUS
(opportunistic)

20. Signs of malignancy
-High nuclear:
cytoplasmic ration
-Rapidy dividing cells
-Monomorphism in cell
type, pleomorphism in
size
-Basophilia (more
purple)
Malignant Epithelial
Neoplasm

21. • Raft arrangement – epithelial cell neoplasia
• Moderate – marked variation in size
• Huge nucleus: cytoplasmic ratio
• Very basophilic (bcos of ribosomes)
• Chromatin unwind, and hv more mitotic figures
• SQUAMOUS CELL CARCINOMA!!!

22. Skin Lump on Dependant Midline

23. Toluidine Blue Stain - Lipoma

24. Cytoplasm fading off, cell X
obviously ruptured –
mesenchymal cells Large
nucleus
Sieve-like, ropy
Large variation chromatin
in size

25. Spindle Cell Neoplasm
• Normal spindle cells have a lot of ctoplasm
– This one has way too much nucleus
– Large variation in size
– Sievelike, ropy chromatin
• THIS IS MALIGNANT!
• Osteosarcoma
• Leiomyosarcoma
• Fibrosarcoma

26. Melanoma
Never benign – treat as mast cell tumour
Appear like histiocytes – fried egg appearance
Look for pigment

27. Lymph Node

29. Lymph Node

30. Histiocyte – Mixed population –
Neutrophils not neoplasia, bcos
bean shape
neoplasia is clonal.
Lymphoblast
precursors
Reactive Hyperplasia
A lot of plasma cells - reactivity

32. Lymphosarcoma
Ruptured
basket cells
Very homogenous: normal should be 50-75% small mature, the
rest larger immature. Here, cells all arrested @ blastic stage

34. Large immature
Small mature
A lot of neutrophils, though no toxic Lymphadenitis
change

35. Discrete Cell
Purple Granules
Metastasized Mast Cell
Tumour