Muestras adecuadas

Las muestras pueden ser no satisfactorias debido a la presencia de sangre, frotis muy gruesos, fijación al aire de frotis fijados con alcohol o un número inadecuado de células foliculares.

Las muestras que contienen por lo menos cinco grupos de células foliculares, cada uno compuesto de al menos diez células, son consideradas satisfactorias para evaluación.

Con experiencia, la tasa promedio de “no satisfactorios” es de un 5% a un 10%. Es incorrecto considerar muestras no satisfactorias o no diagnósticas como negativas. La tasa mas baja de no satisfactorios se alcanzara mediante una cooperación cercana entre el clínico y el citopátologo y con la evaluación inmediata del material.


A follicle lined by bland thyrocytes. At least 5 such groups should be identified. In additon a macrophage with a typically vacuolated cytoplasm and a background of fluid colloid (bluish) can be seen.
A group comprising 3-4 normal follicles. The nuclei are round and the chromatin fine; cytoplasm is abundant, pale and indistinct. A peripheral "flare" is seen on the cell membrane, suggesting hyperfunctionality.
The result of an FNA with a 25G needleon a benign thyroid nodule. Note the very small central haemorrhage. There appears to be a correlation between entity of changes and size of needle, if prominent these changes may hamper histological correlation.
Inadequate smear (blood). A clearly inadequate smear at low power, showing blood only. Even if occasional thyroid cells may be present their identification is greatly hampered by excessive blood. Feed back between the sample taker and the cytologist are essential in order to decrease the number of such cases. The thyroid being a very vascular organ however, even in optimal circumstances a small proportion of cases will be inadequate.