Pineal masses commonly present with Parinaud syndrome, a triad consisting of upgaze restriction, convergence-retraction nystagmus, and pupillary light-near dissociation from compression of the quadrigeminal plate. cThe differential diagnosis for pineal region tumors includes germ cell tumors, pineal parenchymal tumors, glioma, atypical teratoid rhabdoid tumor, and metastatic disease. While exceedingly uncommon, primary pineal melanoma is also a known histopathologic entity that is suspected to arise from melanocytes in the pia mater of the pineal gland. c Primary pineal melanoma is often treated with surgical resection, radiation, and either chemotherapy or immunotherapy. Some patients have received targeted therapy (such as vemurafenib in patients with BRAF V600E mutation) with varying degrees of success.
Oy-sters cCSF sampling can assist in the diagnosis of pineal tumor, specifically to test for germ cell tumor markers (α-fetoprotein, β-human chorionic gonadotropin, placental alkaline phosphatase), systemic tumor markers such as carcinoembryonic antigen, cell-free DNA, or malignant cells on cytopathology. c Pineal tumors can result in obstructive hydrocephalus; therefore, lumbar puncture is not always a feasible option due to the risk of herniation. In patients with melanoma of the CNS, a careful survey consisting of systemic imaging and total body skin examination are warranted to exclude a separate primary melanoma lesion.
cThe differential diagnosis for rapidly progressive bilateral sensorineural hearing loss includes meningitis, superficial siderosis, ototoxicity, and leptomeningeal disease. Difficulty in speech comprehension in excess of pure tone audiometry may suggest involvement or compression of the inferior colliculus.A 62-year-old man presented with 5 months of rapidly progressive bilateral hearing loss. He was evaluated by a local provider who ascribed his symptoms to normal aging and prescribed hearing aids. The patient then developed intermittent binocular diplopia. He denied personal or family history of malignancy. Neuro-ophthalmologic examination revealed light-near dissociation with minimal retraction nystagmus on upward gaze consistent with Parinaud syndrome (eFigure 1, data available from Dryad; doi.org/10.5061/dryad.cvdncjt2w). No papilledema was seen. Audiometry showed moderate to severe high-frequency bilateral sensorineural hearing loss and absent word recognition skills. The remainder of his neurologic examination was unremarkable.Contrast-enhanced MRI of the brain demonstrated an intrinsically T1 hyperintense contrastenhancing mass in the pineal region with extension into the tectum, midbrain, and bilateral thalami, and protruding into the third ventricle, resulting in ventriculomegaly (Figure 1). The