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Mitoses Examples
Taryn A Donovan, Christof A Bertram, Michael J Dark, Frances Moore, and Donald J Meuten
The following images contain structures that are possible mitotic figures (MF) in canine cutaneous mast cell tumors. Please look at each structure and try to decide whether or not you would include this structure when performing a mitotic count (MC).
Answers are based on morphology of the structures and staining characteristics with PHH3 (Phosphorylated Histone H3).
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[q]Does this represent a mitotic figure?
[a]Yes – this is a mitotic figure!
Irregular contour / spikes
Hyperchromatic, linear, pale cytoplasm
[q]Is this a mitotic figure?
[a]Yes – AMF
Spikes, chromosomes detached from linear plate (lagging)
NOTE: Another mitotic figure is in the lower right (metaphase mitosis)
[q]Is this a mitotic figure?
[a]No – MLF
No spikes, round, hyperchromatic regions, eosinophilic “cytoplasm”
[q]Is this a mitotic figure?
[a]Yes – MF
Two separated aggregates (anaphase).
NOTE – not staining with PHH3 due to late stage
[q]Is this a mitotic figure?
[a]Yes – MF
Oval/linear, rods/spikes, pale cytoplasm, prometaphase/metaphase
Note: MF on the right is telophase, not staining with PHH3 due to late phase
[q]Is this a mitotic figure?
[a]No – MLF
No spikes, smooth contour, eosinophilic cytoplasm (not as helpful in this case as slide is eosinophilic)
Note: structure above is also MLF
[q]Is this a mitotic figure?
[a]No – MLF
Ring shape, no spikes, nuclear membrane Note: structure immediately to the left is also MLF
[q]Is this a mitotic figure?
[a]Yes – MF
Ring shape, no spikes, nuclear membrane
Ring metaphase – normal mitotic figure
[q]Is this a mitotic figure?
[a]Yes – MF
Hyperchromatic, irregular contour with rods/spikes Note: Might be normal MF or AMF with chromosome lagging.
Regardless, it is still counted toward the MC
[q]Is this a mitotic figure?
[a]Yes – MF
Three linear chromosome clusters, rods/spikes, lagging chromosomes.
Cell above is a ring metaphase mitotic figure
[q]Is this a mitotic figure?
[a]No – MLF
Hyperchromatic, multiple, smooth/round contour, eosinophilic cytoplasm (slide is eosinophilic)
Note: Also metaphase MF to the lower left
[q]Is this a mitotic figure?
[a]Probably…
Morphology not supportive, stains with PHH3. Consensus – don’t count!
Note: Structure to the lower right staining with PHH3 is also not compatible with a MF
[q]Are these mitotic figures?
[a]Yes – 2 MFs
2 separated chromosome clusters, cells still connected (possible thin connection on lower right) Note: Not staining with PHH3 due to late phase
[q]Is this a mitotic figure?
[a]Yes – tripolar AMF
3 chromosome clusters, separated, anaphase, spikes/projections visible. Represents multipolar (tripolar) AMF
[q]Is this a mitotic figure?
[a]Yes – MF
2 separated chromosome clusters, anaphase, with visible spikes/projections Purple material in center not definitive for chromosome fragment Note: Light staining with PHH3, variable staining in late phases
[q]Is this a mitotic figure?
[a]No – MLF
Multiple, hyperchromatic, smooth contour, eosinophilic cytoplasm (not as helpful here, as slide is eosinophilic)
[q]Is this a mitotic figure?
[a]Yes – MF
2 separated aggregates, cell borders may be connected in a plane we cannot see
Note: Not staining with PHH3 due to late phase
[q]Is this a mitotic figure?
[a]Yes – one or two MF?
Stains well with PHH3 so probably not telophase. May represent 2 adjacent prometaphase MF Note: Likely interpathologist variation in interpretation
[q]Is this a mitotic figure?
[a]Yes – AMF
2 chromosome clusters, irregular contour with spikes/projections, asymmetric bipolar AMF
[q]Is this a mitotic figure?
[a]No
PHH3 positive, but not enough morphologic features to support MF on H&E, so cannot include in MC
Note: Counting definitive MF is recommended
[q]Is this a mitotic figure?
[a]Yes – AMF
2 separated clusters, small connection between clusters (chromosome bridging), irregular contour
[q]Is this a mitotic figure?
[a]No – cannot count as MF
We cannot count this structure because the morphologic criteria for MF are not fulfilled
Note: additional metaphase MF (upper left)
[q]Is this a mitotic figure?
[a]Yes – AMF
Multiple chromosome clusters (multipolar AMF), four linear plates, PHH3 obscures morphology. Adjacent cells with cytoplasmic staining are not counted
[q]Is this a mitotic figure?
[a]Yes – MF
Dense cluster in center of cell (prometaphase MF), spikes/projections easy to see
[q]Is this a mitotic figure?
[a]Yes – MF
Dense hyperchromatic cluster (prometaphase MF), contour is irregular, but spikes/projections difficult to see
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