Presentation
Mass.
Patient Data
Large well-defined right infratemporal soft tissue mass is T1 isointense, avidly enhancing with central areas of non-enhancement. Its medial extent is to just below the foramen ovale without intracranial extension. Laterally it extends into temporalis, abutting the base of skull which it remodels. No intracranial extension.
Conclusion: Mass most likely to represent a nerve sheath tumor. Given it's location and ascent into temporalis it is likely arising from deep temporal branches of the mandibular division of the trigeminal nerve.
Under ultrasound guidance, using an 18 gauge Quickcore needle, 2 core samples of the lesion at its supra-zygomatic location immediately deep to the temporalis were performed. The lesion was entered from its anterior margin with the needle directed posteromedially. The core samples were sent in formalin for histological analysis. No immediate post procedure complications.
Case Discussion
The core biopsy confirmed the diagnosis.
Histology
MICROSCOPIC DESCRIPTION: Sections show a spindle cell tumor composed of poorly formed intersecting fascicles. There are focal pallisaded tumor nuclei, consistent with Verocay body formation. There is mild nuclear atypia with nuclear elongation and hyperchromasia. There are scattered lymphocytes, together with foamy and hemosiderin laden macrophages. No mitoses or necrosis are seen. There is no evidence of malignancy. Immunohistochemical results show tumor cells stain: S100+, SOX10+, CKAE1/3- and EMA-.
FINAL DIAGNOSIS: Schwannoma.