Bilateral Dilated Pupil in Dorsal Midbrain Syndrome

Abstract

A 19-year-old female presented with complaints of eyestrain and a self-reported abnormally dilated pupil for 1 month. She suffered from major depression managed with regular psychiatric visits. Her vision was 6/6 in both eyes. Intraocular pressures were normal. A pupil examination showed mild dilated pupils with vermiform movements bilaterally. She was diagnosed with bilateral Adie’s pupil and began 1% pilocarpine treatment. One month later, her pupils remained dilated with poor light reflexes. Pupil sizes were 5.5 mm OD and 5.0 mm OS and constricted to 5.0 mm OD and 4.5 mm OS 40 min after conducting a 0.1% pilocarpine test. Extraocular movements revealed limited upgaze in both eyes (Fig. 50.1). Her upgaze palsy was accompanied by convergent retraction nystagmus when she looked upward (Video 50.1). Neuroimaging studies were performed under the impression of dorsal midbrain syndrome. A CT scan revealed a soft tissue lesion over the pineal region (Fig. 50.2). An MRI showed a lesion that was isointense on T1-weighted and mildly hyperintense on T2-weighted images, which enhanced well after contrast injection (Fig. 50.3). She underwent a craniotomy at another hospital, and the pathological report revealed a germinoma.