Large Lateral Parapharyngeal Congenital Teratoma Presenting in an Adult

Introduction

Teratomas are germ cell tumors that arise in totipotent cells. They are generally composed of tissues from more than one germ cell layer [1]. Head and neck teratomas are rare, accounting for less than 5% [2, 3]. Cervical teratomas are even uncommon usually midline, and most of them usually present in pediatric age group. In this article, we report a case of extensive benign lateral teratoma in a 17-year-old girl.

Case Report

A 17-year-old girl presented with swelling at left side of face and neck. She gave history of a painless swelling present since birth, gradually increasing in size. It was causing a bulge in left parotid area extending superiorly up to temporal region. The mass was fungating over the submandibular and upper neck area. Patient had no difficulty in opening the mouth. The fungation into neck started 3 years prior. Swelling was clinically immobile with extension felt deep to mandible. Patient had associated ear discharge but no facial palsy. She underwent multiple consultations at many centers, and it was assumed unresectable (Fig. 1). Patient underwent MRI head and neck with gadolinium contrast showed large left parapharyngeal and masticator space lesion with soft tissue, fat, and fluid intensity areas, extending into the floor of the middle cranial fossa and petrous apex. The skull base bone appeared expanded (Fig. 2a, b). Multiple superficial biopsies done at different centers show benign fibrous tumor.

Fig. 1.

Preoperative photograph showing the fungating tumor

Fig. 2.

a MRI scan, axial view, T1 with gadolinium contrast. b MRI scan, sagittal view, T1 with gadolinium contrast

Surgical Procedure

Incision was made around protruding tumor in the submandibular region, extended to the ipsilateral preauricular skin crease. A midline lip split was also made. Mandible was exposed, and a paramedian mandibulotomy was done after pre-plating. Exposure of carotid bifurcation and internal jugular vein was done. Internal carotid artery was separated from tumor bed and traced upward. Tumor was immobile even after mandibulotomy. A total conservative parotidectomy was done to expose the deep parapharyngeal space. Mandible was swung laterally after division of stylomandibular ligament. Transection of zygomatic arch was also done. The tumor was then mobilized from skull base by finger dissection and was delivered in toto (Fig. 3), leaving an intact exposed dura. There was a shell of expanded bone seen in skull base (Fig. 4). Wound was closed. Defect was left alone. No reconstruction was required. Postoperative period was uneventful. Patient had a left facial weakness.

Fig. 3.

Resected specimen

Fig. 4.

Postoperative defect showing the expanded bony skull base

Histological examination showed ectodermal derivatives consisted of keratinized squamous epithelium covering the wall of the cyst, skin adnexal structures, mature glial tissue, cartilage, muscle, and fat, suggestive of a mature cystic teratoma. Representative views showing mature cartilaginous tissue with benign chondrocytes (Fig. 5a), stomach foveolar epithelium with pits (Fig. 5b), and mature glial tissue and strip of columnar epithelium (Fig. 5c) are shown. After 6 months of clinical follow-up, she has minimal facial deformity due to bone expansion. The facial nerve paresis recovered fully (Fig. 6). There was no functional impairment.

Fig. 5.

a Histopathology showing mature cartilaginous tissue with benign chondrocytes. b Histopathology showing Stomach foveolar epithelium with pits. c Histopathology showing mature glial tissue and strip of columnar epithelium

Fig. 6.

Postoperative photograph at 6-month follow-up

Discussion

Teratomas are embryonal neoplasms that arise when totipotential germ cells escape the developmental control of primary organizers and give rise to tumors containing tissue derived from all three blastodermic layers. They can occur in various sites and organs [4].

Head and neck teratomas are rare, usually presenting in pediatric age group. Ninety percent of the tumors are reported in children [5]. Bizarre pathological appearance and unpredictable behavior characterizes such tumors [6]. Such teratomas presenting in adult age group are rare [4, 7–9]. Most cases present as midline masses. Presentation as a lateral mass is also rare. There is a report of a case of mediastinal teratoma extending to the neck as a mass [7]. Malignant transformation of cervical teratoma has been reported [10].

Present case is unique due to its lateral and massive nature of presentation in an adult. This is probably the fifth such case in literature. The treatment was delayed due to assumed inoperability. Though clinically lesion was massive and disfiguring, intraoperatively surgical planes were maintained. A combination of trans-cervical, trans-mandibular, trans-parotid, and trans-zygomatic approach was needed to mobilize all the spaces to remove the tumor in its entirety.