Metastasis or Metamorphosis

A 36-year-old woman presented in December 2013 with double vision. Three weeks prior, she had a new headache that was relieved with an occipital nerve block. Three days before, she had acute onset of horizontal binocular diplopia that was worse with left gaze. She denied dizziness, nausea, vomiting or weight loss. Her neuro-ophthalmic exam was remarkable for a left eye abduction deficit. MRI of the brain and orbits, from an outside facility, was read as negative for an intracranial mass/lesion. In April 2014, she returned with continued diplopia and new complaints of severe headache, weight loss, night sweats, vertigo and difficulty with balance. Exam showed a left 6th nerve palsy, absent corneal reflexes, and bilateral facial paralysis. A lumbar puncture showed mild leukocytosis, elevation of protein, and normal flow cytometry and cytology. All lab tests were within normal limits. Brain MRI showed enhancement in the left cerebellopontine angle, multiple cranial nerves, skull base dura and leptomeninges. A 5-day course of IV steroids was undertaken without improvement of symptoms. Brain biopsy showed an illdefined soft mass. Pathology showed a benign epidermoid cyst. A second tissue biopsy was done because of high suspicion for malignancy, which showed a poorly differentiated infiltrating squamous cell carcinoma. There was no evidence for a primary tumor by whole body PET.