Management of Multicentric Myopericytoma in the Maxillofacial Region: A Case Report
The patient was a 42-year-old Chinese woman who presented with a 10-year history of slowly growing masses in the maxillofacial region. In 1997, the patient found a mass in the back region of her right ear, and the diagnosis based on a biopsy of the mass was merely a benign tumor. Shortly after the excision, another mass emerged and gradually enlarged below the right earlobe region. The patient refused tumor excision due to fear of the surgery.\nSince the patient was referred to the Department of Head and Neck Oncology, West China Hospital of Stomatology, Sichuan University, in 2007, she had been feeling slight pain in the mass of the right parotid gland. Physical examination revealed an approximately 6 × 5-cm mass in the region of the right parotid gland. It was a multinodular lesion without mobility and tenderness, and positive to the position changing enlargement test. There was no evidence of sensory deficit or facial palsy. On panoramic radiography, there was a small-sized deformity in the right ramus. The computed tomography (CT) scan demonstrated multicentric soft tissue masses in the region of the right parotid gland, cheek, infratemporal fossa and parapharyngeal spaces; these masses enhanced peripherally with central heterogeneous irregular nonenhancement after administration of a contrast medium (fig. ).\nTo reduce blood loss during surgery, digital subtraction angiography (DSA) and superselective embolization were performed prior to the operation. DSA disclosed soft tissue in the right parotid gland region, with an abundant blood supply from branches of the right external carotid artery. With a guide wire, a 5F sheath was used to superselectively catheterize the subbranches of the right external carotid artery and embolize them with 550–750 um PVA particles. Immediate postinjection angiography showed an occlusion of the subbranches to the focus (fig. ).\nUnder general anesthesia, the mass in the right parotid gland region was completely excised without much blood loss. It was light yellow and about 6 × 5 × 5 cm. In attempting to remove other masses in the parapharyngeal space, the authors removed the right ramus and tried to pass through the lateral and medial pterygoid muscles. Unfortunately, there was a lot of blood loss from the pterygoid venous plexus and, at that time, the total blood loss had reached about 1,600 ml. The authors had to give up the removal of the other masses in the parapharyngeal space. The patient had an uneventful recovery, except for right facial palsy, and was discharged 7 days following the operation.\nThe lesion was identified as MPC. The pathological findings showed numerous gaping and branching, and thin-walled vessels concentrically surrounded by spindle ovoid myoid tumor cells with eosinophilic cytoplasm (fig. ). Hyalinization was present, but there was no necrosis, nuclear anaplasia, increased mitoses or infiltrative growth. There was positive immunoreactivity for SMA, MSA and desmin, but CD34 and CD99 staining were negative.\nThe patient had no more pain and was reviewed at 3- to 6-month intervals. There was no sign of recurrence in the right parotid gland region, and there was no obvious enlargement in the residual lesions 5 years postoperatively. She has had regular follow-up.