Case Report A rare ectopic localization of pleomorphic adenoma Ejeil A.-L. a, *, Moreau N. a , Le Pelletier F. b a Bretonneau hospital, service d’odontologie, 2, rue Carpeaux, 75018 Paris, France b Department of oral and ENT pathology, Pitie ´-Salpeˆtrie `re hospital, department of dermatology, Cochin-Port Royal hospital, Paris France 1. Introduction Pleomorphic adenoma (PA) also called mixed tumor is the most common benign salivary gland tumor accounting for 50% of all salivary gland neoplasms. It can involve major as well as minor salivary glands [1]. Among minor salivary glands (5–10% of cases) the palate, lip, nasal cavity, pharynx, larynx and trachea are the most common sites [1]. Diagnosis is made upon histopathological examination. Wide excision is the treatment of choice to avoid recurrence. We report a case of ectopic pleomorphic adenoma localized in the alveolar mucosa of the right mandibular retromolar trigone. 2. Case report A 25-year-old healthy female patient was referred by her dentist to the department of oral medicine of the Bretonneau Hospital in Paris following the appearance of a swelling on the right side of her lower jaw near the retromolar trigone. Her ipsilateral third molar had been extracted a few years ago without any complications. The patient reported recent discomfort, leading her to consult her dentist. Swelling progressed gradually up to the present size [at time of consult) responsible for a mild discomfort but no pain. Extra-oral clinical examination did not reveal any anomaly and regional lymph nodes were not enlarged. Endobuccal examination revealed a 1-cm wide localized swelling located on the right retromolar trigone in the region of tooth 48 (extracted a few years ago) (Fig. 1). Swelling was firm on palpation. The overlying mucosa was normal in color and texture. The rest of the endobuccal examination was strictly normal. Radiographic examination (retro-alveolar) was unremarkable. Differential diagnosis included lipoma, fibroma, pleomorphic adenoma and mucoepidermoid carcinoma. In view of the localization of the lesion and its evolving nature (progressive increase in size since being noticed by the patient) complete excision of the lesion was indicated. Complete excision of the lesion with safety margins was planned. Under local anesthesia, incision of the overlying mucosa was carried out following by careful dissection. Intra-operative macroscopic assessment showed an encapsulated tumor. After removal of the tumor, layered closure of the mucosa was carried out with 3-0 VICRYL 1 tension-free interrupted sutures. The excision specimen was fixed with formalin (10% solution) and sent to the pathology laboratory for histological analysis. A post- operative prescription comprising an analgesic (1 gram of paracetamol 4 times a day in case of pain) and a chlorhexidine mouthwash (3 times daily for five days) was given to the patient. Histopathological examination revealed a well-defined, encap- sulated tumor without neural involvement. The stroma was focally myxoı ¨d in which anastomosing trabeculae and ducts with squamous differentiation could be observed. An uninvolved normal salivary gland lobule was seen beyond the capsule J Stomatol Oral Maxillofac Surg xxx (2018) xxx–xxx A R T I C L E I N F O Historique de l’article : Received 25 June 2018 Accepted 25 November 2018 Keywords: Pleomorphic adenoma Minor salivary gland Retromolar area A B S T R A C T Introduction: Pleomorphic adenoma (PA) is the most common benign salivary gland tumor, frequently affecting the major salivary glands but also the palatal or labial minor salivary glands. Pleomorphic adenomas affecting the retromolar trigone have seldom been reported with only few cases described in the literature. Observation: We present the case of a young female patient who presented with this rare localization of pleomorphic adenoma and its subsequent management. Discussion: Pleomorphic adenoma of the retromolar trigone is a rare occurrence. Nevertheless, when faced with a swelling of the retromolar trigone, a diagnosis of pleomorphic adenoma should not be omitted from the differential.  C 2018 Elsevier Masson SAS. All rights reserved. * Corresponding author. E-mail address: anne-laure.ejeil@parisdescartes.fr (A.-L. Ejeil). G Model JORMAS-607; No. of Pages 2 Please cite this article in press as: Ejeil A-L, et al. A rare ectopic localization of pleomorphic adenoma. J Stomatol Oral Maxillofac Surg (2018), https://doi.org/10.1016/j.jormas.2018.11.016 Available online at ScienceDirect www.sciencedirect.com https://doi.org/10.1016/j.jormas.2018.11.016 2468-7855/  C 2018 Elsevier Masson SAS. All rights reserved.