Pearls and oy-sters: Primary pineal melanoma with leptomeningeal carcinomatosis - Supplemental figures

Pearls:

Pineal masses commonly present with Parinaud syndrome, a triad consisting of upgaze restriction, convergenceretraction nystagmus, and pupillary light-near dissociation from compression of the quadrigeminal plate.
The 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.
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:

Cerebrospinal fluid (CSF) sampling can assist in the diagnosis of pineal tumor, specifically to test for germ cell tumor markers (alphafetoprotein, beta human chorionic gonadotropin, placental alkaline phosphatase), systemic tumor markers such as carcinoembryonic antigen, cell-free DNA or malignant cells on cytopathology.
 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 central nervous system (CNS), a careful survey consisting of systemic imaging and total body skin examination are warranted to exclude a separate primary melanoma lesion.
The 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.

Methods
Supplementary Figure 2. Image taken during endoscopic biopsy demonstrating dark material (melanin) lining the third ventricle.

Supplementary Figure 3. Pathologic specimens. H&E (A) stained section demonstrating high-grade pigmented epithelioid neoplasm. Differentiation marker immunophenotyping (B) with staining for HMB45, MART1, tyrosinase) consistent with melanoma.