Pleomorphic Adenoma of the Accessory Parotid Gland


Austin J Otolaryngol. 2014;1(1): 3.

Pleomorphic Adenoma of the Accessory Parotid Gland

Hiroyoshi Iguchi* and Hideo Yamane

Department of Otolaryngology and Head & Neck Surgery, Osaka City University Graduate School of Medicine, Japan

*Corresponding author: Hiroyoshi Iguchi, Department of Otolaryngology and Head & Neck Surgery, Osaka City University Graduate School of Medicine: 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan

Received: May 18, 2014; Accepted: May 20, 2014; Published: May 22, 2014


Salivary gland; Accessory parotid gland; Pleomorphic adenoma; MRI; Surgery


APG: Accessory Parotid Gland; PA: Pleomorphic Adenoma; CT: Computed Tomography; MRI: Magnetic Resonance Imaging; FNAC: Fine–Needle Aspiration Cytology


The accessory parotid gland (APG) is commonly located anterior to the main parotid gland, between the zygomatic arch and the Stensen duct, and attached to the masseter muscle. The APG is connected to the Stensen duct by one or more tributary ducts [1]. The incidence of APGs is 21–61% [2]. However, APG tumors are rare with an incidence of only 1–7.7 % of all parotid gland tumors [1,3]. All tumor pathologies that occur in the main parotid gland may also occur in the APG. According to previous reports, the most common subtype of benign APG tumors is pleomorphic adenoma (PA) [4,5]. Newberry et al. reported that 58.6% of benign APG tumors were PA [4], and in our previous study on 65 APG tumors in Japan, PA accounted for 80.6% of benign APG tumors [6].

Here, we describe a typical case of a large PA of the APG treated in our hospital. A 35–year–old man presented with a 5–year history of a slow–growing, right mid–cheek mass in the pre–parotid region. The mass was mobile with a smooth surface. He denied tenderness on palpation and facial weakness. Computed tomography (CT) of the neck confirmed a well–circumscribed and heterogeneously enhanced, 36 × 23–mm–sized mass situated anterior to the right main parotid gland and on the surface of the masseter muscle (Figure 1).The ovoid mass demonstrated low and heterogeneously highsignal intensity on T1– and T2–weighted magnetic resonance imaging (MRI), respectively, and heterogeneous enhancement on contrast–enhanced T1–weighted MR images. A time–signal intensity curve on dynamic MRI revealed a gradual enhancement pattern (Figure 2). Ultrasonography–guided fine–needle aspiration cytology (FNAC) indicated PA. Standard parotidectomy incision with anterior extension was chosen for complete and safe exposure of the mass, facial nerve branches, and Stensen duct. The mass with the surrounding salivary tissue was completely separate from the main parotid gland and connected to the Stensen duct via a tributary duct.The mass was completely resected without damaging the tumor capsule, facial nerve branches, or Stensen duct (Figure 3). The intraoperative pathological diagnosis using a frozen specimen was PA. The tumor was well encapsulated and solid, and the cut surface was yellowish white (Figure 4). Postoperative complications such as facial weakness and salivary fistula were not observed.