10/21/2008 Case 4: Pineoblastoma (WHO grade IV) 

Presented by: Dr. Ehud Lavi - New York Presbyterian Hospital

Clinical History:

A 57-year-old woman presented in 2002 with a pineal region mass that was investigated by MRI showing a relatively well circumscribed pineal mass of several centimeters, and a small biopsy was taken. There was a recurrence in 2008, when the patient had a fall, urinary incontinence and ataxia. In the intervening six years, there had been no treatment or symptoms. The initial biopsy showed a small-cell lesion that had rosettes and the nuclei and other features did not suggest any anaplasia. There were few if any mitotic figures, and no apoptotic bodies were found. The Ki-67 mitotic labeling index was very low (hardly any positive nuclei were present on a projected image). In 2008, she had papilledema during a follow-up examination for diabetes, and this prompted further investigation. The daughter then reported a 6-week period of episodic mutism. The patient was found to be mute, and MRI showed a very large pineal region mass and obstructive hydrocephalus. Surgical debulking was undertaken. The recurrence was high-grade with nuclear pleomorphism and mitoses. The Ki-67 labeling index was very high in the 2008 specimen. The tumor was synaptophysin positive, focally neurofilament positive, and negative for NeuN, GF AP, cytokeratin and leukocyte common antigen. There was a discussion lead by Dr. Lavi regarding sampling error on the first sample versus tumor progression.

Diagnostic Notes:

The 2002 tumor may have been a pineocytoma (WHO grade I) or pineal tumor of intermediate grade (WHO grade II-III), and given the 6 years until recurrence, there was most likely progression from a low-grade tumor to a high-grade tumor, diagnosed as a pineoblastoma (WHO grade N), rather than the presence of any high-grade tumor to begin with.

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