Fine-needle aspiration cytology is an effective diagnostic tool in paediatric patients with mucoepidermoid carcinoma as secondary neoplasm

Background: Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumour in paediatric population, accounting for 16% of all cases. Patients affected by a previous solid or leukaemic neoplasm during their childhood may develop a second different tumour during the follow-up. In this setting, salivary gland MEC is relatively frequent, accounting for 6% of the second neoplasms in paediatric patients. Consequently, the occurrence of salivary gland nodules in paediatric patients with a previous neoplasm should be considered an event with a high risk of malignancy that poses peculiar diagnostic challenges. Summary: This study was designed to define clinical and instrumental findings and morphological features of MEC on fine-needle aspiration cytology (FNAC) samples in paediatric patients with and without a previous neoplasm. Five patients under 19 years are included in this series. FNAC was performed in all patients on a parotid nodule. We have identified 2 groups of patients: (a) 2 cases with previous history of malignancy (acute lymphoblastic leukaemia and Hodgkin lymphoma) and (b) 3 cases without previous malignant neoplasms. In all cases, a final diagnosis of MEC was rendered. Key Messages: MEC may occur as a second malignancy in paediatric patients. FNAC is certainly a valid and accurate diagnostic tool for this type of neoplasm, even in the paediatric age, allowing the correct management of the patients.