The paper reports a case of a 13-year-old girl with parotid mucoepidermoid carcinoma (MEC). From 7 months she presented with an isolated, solid, non-inflammatory, painless mass of the left parotid gland (6 x 4 x 3.8 cm); she was treated with one-week anti-inflammatory therapy in the suspicion of parotitis. Because of persistence of symptoms, she was submitted to ultrasonography of the mass and to fine needle biopsy that pointed toward a malignant disease. In the pre-surgical assessment the computed tomography showed no other abnormalities apart from the primary lesion so that the patient received complete surgical excision of the mass including neck dissection; facial nerve was rescued. Histopathological results revealed a low grade MEC. Although it was classified as a low grade, a loco-regional radiation dose of 60 Gy in 30 fractions over 6 weeks was administered because of positive microscopic margins, perineural invasion and regional nodal dissemination.