Differerential diagnostics of intranuclear holes
Papillary cancers - Case 25

The images demonstrate the differential diagnostic of intranuclear holes. These may be projections of extranuclear vacuoles (marked with yellow in the image) or pathognomic inclusions (marked with red) or drying artifacts. The shape of a pathognomic inclusion is regular, round with sharp borders. The latter is a dark rim of condensed nuclear membrane.

Papillary cancers - Case 38

Intranuclear holes marked with green arrows are only projections of extracellular vacuoles, while characteristic inclusions are marked with red.

Papillary cancers - Case 65

It is worth analyzing thoroughly the inclusion pointed with red arrow. It is not an artifact caused by projection of a vacuole seen elsewhere on the smear. Note that through this inclusion we can see the contours of another nucleus located under that which contains the whole. This is the essence of intranuclear inclusion: it is an invagination of nuclear membrane which punches in the nucleous. The nature of all other intranuclear holes in the image is doubtful, we can found holes which are with great probability pathognomic inclusions (e.g. two marked with green) while others are more likely are only projections (see nuclei marked with yellow).

   
Follicular adenoma - Case 10

Note that intranuclear pseudo-inclusions are related to the vacuolization. The vacuoles within the cells are identical to those outside the nuclei. Overinterpretation should be avoided. It is worth analyzing the hole in the right image marked with green arrow. This hole exceeds the border of the nucleus. It is the absolute proof against an intranuclear inclusion.
   
Chronic lymphocytic thyroiditis - Case 25

The nuclei are light and the chromatin is condensed to the periphery. There is a suspicious hole in the right image. This is not absolutely round but is surrounded with a dark rim.
   
Follicular adenoma - Case 2

Two cells marked with green arrows contain inclusion-like empty holes. These are probably drying artifacs because most of the remaining cells have similar, but not round empty intranuclear holes. If the latters are drying artifacts than we can conclude that the regular, round inclusions are also such projections. Drying artifact are not regularly round, they have not sharp but blurred borders and lack dark rim around the hole.
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