Lateral Cystic and Solid Lesions

The lateral cyst and solid lesions are situated in the region of the posterior triangle of the neck. These lesions can be derived from infectious, inflammatory, congenital, traumatic, benign, or malignant neoplastic processes. Lesions in the head and neck are especially adequate targets for fine needle aspiration cytology (FNAC) because it is cost-effective, rapid to perform, and minimally invasive. The main goal of the FNAC is to determine the presence or absence of a neoplasm. The diagnostic accuracy of FNAC is over 90%. In this chapter, we aimed to describe the cytological features of the main cystic and solid lesions, such as epidermal inclusion cyst, dermoid cyst, branchial cyst, lymph node benign lesions, and metastasis in cervical lymph nodes, focusing on the differential diagnosis between these entities.