Fooled Thrice

He underwent left orbital apex decompression and biopsy of the lesion. Pathology revealed a high-grade malignant peripheral nerve sheath tumor. There was a fascicular architecture with staghorn-like vasculature, heterologous cartilage formation, and high mitotic activity. After tissue diagnosis, mycophenolate and corticosteroids were stopped. Whole-body PET-CT was performed and was negative for metastatic disease. After extensive discussion among multiple services, he underwent resection of the tumor via a left cranio-orbital zygomatic craniotomy with extradural clinoidectomy and exenteration of the frontal and ethmoidal sinuses and orbit. The tumor surrounded the carotid artery and extracapsular dissection was not possible. One month after surgery, repeat MRI revealed that the tumor had significantly increased in size particularly in the region of the left cavernous sinus. Due to the aggressive nature of the tumor, further surgery was not recommended and he underwent fractionated radiation therapy over 6 weeks and received two doses of cisplatin. Follow-up MRI one month after radiation and chemotherapy demonstrated decreased tumor size in the region of the left sella and cavernous sinus. The visual function in his right eye remained normal. This malignant tumor was likely present initially and the radiation therapy produced a response large enough to improve his symptoms, but insufficient to eradicate the tumor. This resulted in a recurrence of his symptoms 18 months after radiation therapy. Although a malignant transformation was possible, the unusual reduction in size seen after his initial treatment and the relatively short latency period argued against this. Malignant oculomotor nerve sheath tumors are extremely rare and have been reported in a 9-year-old boy with additional cranial nerve schwannomas [1] and a 72-year-old man with a complete, pupil-sparing oculomotor nerve palsy that completely resolved after surgical resection.