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The presence of inclusions is the most specific sign of a papillary
carcinoma. Intranuclear inclusions are invagination of nuclear membrane
- therefore these are in fact pseudoinclusions. One of the most
important tasks of a thyroid cytopathologist is the correct
differential diagnostic of intranuclear holes. These may be projections
of extracellular or cytoplasmic vacuoles and drying artifacts, as well.
The shape of a pathognomic inclusion is regular and round, and presents
a dark rim corresponding to the invaginated and condensed nuclear
membrane. Nevertheless, intranuclear inclusions may be observed not
only in other thyroid malignancies but even in benign cases. The
presence of inclusion is the most important sign of a papillary
carcinoma but has to be considered in combination of other cytological
properties. |
