PMC5241474_01
Endoscopic view of teratoma extending into the oropharynx. Transoral endoscopic view of a large mucosalized mass extending from the nasopharynx into the upper aspect of oral cavity and pharynx and occluding the cleft palate defect. The metal rings represent the reinforced endotracheal tube placed transorally following induction of anesthesia.
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Office endoscopy revealed a complex, mobile, midline mucosalized mass filling the entire posterior nasal airway with extension into the superior oropharynx through a cleft in the soft palate (Figure 1).
CT angiogram (CTA) imaging of pedunculated skull base lesion. (a) Coronal CT slice at level of the bilateral sphenoid sinuses (S), with tumor pedicle arising between sinus cavities, at typical site of intersinus septum. The 4 x 4 cm tumor (T) is composed of heterogeneously dense material, with suspected low-density (dark) fat seen. (b) CTA in sagittal view, showing relationship of tumor pedicle extending between anterior sphenoid sinus (S) and posterior clivus (C). Arrow shows the diminutive artery coursing through the pedicle, without direct communication with the ICA and vertebrobasilar system (not shown).
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Computed tomography angiography (CTA) revealed a 4 x 4 cm multiloculated, nasal mass of the sphenoid skull base protruding through a "central corridor" in the sphenoid intersinus septum of the basisphenoid and anterosuperior to the clivus bone (Figures 2(a) and 2(b)). CTA was also performed out of concern for large caliber vascular pedicle to the tumor, with only limited axial blood supply noted (Figure 2(b)).
Magnetic resonance imaging (MRI) of pedunculated skull base lesion. (a) Coronal T1 MRI clearly demonstrates the tumor extending from intracranial midline defect into the nasopharynx. The bright intensity signal within the tumor (T) and stalk between the sphenoid sinuses (S) on T1 sequence represents fat, nearly pathognomonic of teratoma. Pituitary duplication (P with arrows) is best appreciated on T1 imaging as well. Of note, the left sphenoid sinus was noted to have mucosal thickening at the time of MRI compared to CT imaging (Figure 2). (b) Coronal T2 sequence at same slice location highlights the enlarged midline basilar cistern (Cis) with hyperintense signal representing cerebrospinal fluid.
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Magnetic resonance imaging (MRI) demonstrated a pedunculated, extradural heterogeneous mass extending into the nasopharynx, with high intensity fat signal seen within the tumor and its sizeable stalk on T1 sequence (Figure 3(a)). T2 sequence (Figure 3(b)). The tumor stalk was felt to represent a patent/persistent craniopharyngeal duct, and multiple other midline intracranial abnormalities including corpus callosum dysgenesis, midline lipoma, and dysmorphic hypothalamic and brainstem changes were also noted (not shown).
Use of intraoperative CT image guidance assistance during skull base approach. Computer-assisted navigation system (image guidance) highlighting intraoperative CT scan imaging in coronal, sagittal, and axial views. With the registered instrument tip contacting the anterior face of the lesion (endoscopic image at bottom right), the fine cut maxillofacial CT scan shows calcified material present within the skull base teratoma at this site of tumor contact (intersection point of green lines), representing intratumoral dentition.
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A two-surgeon, four-handed surgical approach, and intraoperative, computer-assisted image guidance confirmed unfettered access to the teratoma, with classic dentition seen in triplanar view (Figure 4).
Surgical resection of skull base teratoma with ultrasonic bipolar diathermy. Endonasal view of the pedunculated skull base teratoma obstructing the posterior nasopharynx, with metal suction tip retracting the left inferior turbinate (a). Following sphenoidotomies, the tumor pedicle is approached (b), clamped in a full-thickness manner (c), and completely transected (d) using the vice-clamp tip and combined ultrasonic/bipolar platform energies. Teratoma passed into the oral cavity for transoral en bloc tumor removal (e), with lesion measuring approximately 4.0 cm in diameter (f).
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Thunderbeat  device, for simultaneous ultrasonic wave (cutting) and bipolar diathermy (coagulation) action. The technique permitted transmural pedicle resection, precluding the need for awkward suture ligation of a thick pedicle adjacent to the skull base, while allowing for the tumor to be delivered en bloc transorally (Figure 5).
Representative histopathology photomicrographs of the skull base teratoma. (a) Stratified squamous epithelium (SE) with associated adnexal structures (4x magnification). (b) Ciliated respiratory epithelium- (RE-) lined cystic structure, salivary gland tissue (SG), and cartilage (CT) (4x magnification). (c) Scattered foci of SG adjacent to CT tissues (10x magnification). (d) Haphazard arrangements of CT, SG, and striated muscle (SM) (10x magnification). Mature adipose tissue is also present in the background (unlabeled clear cell bodies).
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Microscopic analysis of the resected tumor using standard histology revealed a disordered arrangements of mature epithelial and mesenchymal tissues, including cartilage, adipose tissue, stratified squamous epithelium with cutaneous-type adnexal structures, ciliated respiratory-type epithelium, and striated muscle (Figure 6).