An Extensive Lymphatic Malformation of the Parotid and Parotideo-Masseteric Region in an Adolescent: Nerve-Preserving Surgical Management and Postoperative Imaging Follow-Up: A Case Report.

Background: Lymphatic malformations of the parotid gland and of the adjacent parotideo-masseteric region are rare and technically demanding, because the malformation infiltrates the glandular parenchyma and grows around the branches of the facial nerve rather than displacing them, and published experience consists almost entirely of isolated case reports. Case Presentation: A 16-year-old boy was treated for an extensive lymphatic malformation of the left parotid and parotideo-masseteric region, present since childhood and progressive over three years, with facial asymmetry, no pain and normal facial nerve function. Magnetic resonance imaging showed a mixed lesion of 47 × 20 × 55 mm involving the superficial and deep lobe with parapharyngeal extension. Facial nerve-preserving partial parotidectomy of European Salivary Gland Society levels I, II and IV was performed under continuous nerve monitoring. Histology confirmed a cavernous lymphangioma (CD31 and D2-40 positive). A postoperative sialocele was managed after a single revision. Conclusions: Level-classified nerve-preserving parotidectomy with monitoring was associated with stable residual disease and preserved facial nerve function during 19 months of follow-up. The radial resection margin was focally involved and a thin residual lesion persisted on imaging. Stability at follow-up does not establish the absence of future progression, and longer follow-up is required.