Case 802 -- A 49 year-old woman with a pineal mass

Contributed by Alaa Alkhotani, MD1, Todd G Mainprize, MD2, Juan M. Bilbao, MD1
1Department of Pathology and 2Department of Neurosurgery
Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario


A 49 year old woman with a remote history of borderline serous tumor of the right ovary presented with a history of headache, nausea and vomiting. MRI imaging of the brain showed mixed solid and cystic pineal region mass causing obstruction at the level of the cerebral aqueduct associated with marked hydrocephalus (Fig. 1). The patient underwent a third ventriculostomy and pineal region tumor biopsy.


The tumor submitted for neuropathological evaluation consisted of multiple pieces of soft, tan and red tissue ranging in size from 0.2x 0.2 x 0.2cm in greatest dimension. Microscopically the tumor has a distinctive papillary architecture (Figs. 2 and 3). The lining tumour cells are columnar and display slight to moderate nuclear pleomorphism. Tumour cells nucleus has stippled chromatin and a small nucleolus. Mitotic activity is almost negligible. The stroma of the fronds contains variable amount of collagen. True rosettes are not identified. Of note is the presence of cells with a cytoplasmic clear vacuole or eosinophilic condensation of the cytoplasm.

The tumor cells are immunopositive for pankeratin, low molecular weight cytokeratin (LMWCK) (Fig. 4), CK19 (Fig. 5), CD56 (Fig. 6), and focally positive for S100 (Fig. 7). EMA showed focal dot like paranuclear positivity and GFAP was focally positive, mostly labeling the neuropil. The ki67 index was less than 2%. The tumor cells are immuno negative for synaptophysin, CK 7, CK 20, WT-1, ER, PR and CEA. What is the diagnosis?


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