Sampling methods
Simple cytobrush sampling is easier in the oral cavity in case the lesion is localized (vesicular, exulcerated lesions).
Free hand FNAB is useful in superficial lesions since they must be localized and fixed using the sampler’s fingers. Superficial, subcutaneous or submucosus lesions do not need US guidance; most of the US heads are too large for these lesions.
US guidance is useful to avoid complications (bleeding, haematoma) and is absolutely necessary in deep lesions (tumors of nasopharynx, deep lobes of salivary glands) or large cystic lesions. Small lesions localized next to the large vessels also need guidance.
CT guidance is not real time: we may use the CT scan images for localization before a free hand or US guided aspiration.
Staining methods
We may use Giemsa (air dried smears), Papanicolaou or H&E staining as well. Papanicolaou is informative in squamous cell lesions, and so is H&E. Giemsa stained specimens can show metachromasia: extracellular matrix and the cytoplasm of myoepithelial and connective tissue cells show metachromatic purple staining. These cellular and extracellular components play a very important role in the diagnostics of head and neck, especially salivary gland lesions.
Immunocytochemistry can be performed if needed (on cytospin preparared or liquid based material if possible).