Aspiration Cytology of Masses of Superficial Organs

Fine-needle aspiration (FNA) is a minimally traumatic and minimally invasive procedure that allows one to obtain cytologic material from patients’ palpable or non-palpable masses by using palpable and/or ultrasound guidance. The cytologic sample is processed and stained with conventional stains in a timely manner, and results based on smears and cell-block interpretations are usually available in 24–48 hours. Ancillary tests such as flow cytometry, molecular biology, and immunocytochemistry complement the cytomorphologic pattern and are paramount for patient management. This chapter covers the application of immunocytochemistry markers to cytology preparations as a complementary tool for the diagnosis of the most common palpable and non-palpable superficial masses harvested by FNA.