Endoscopic biopsy and third ventriculostomy for the management of pineal region tumors.

OBJECTIVE

To assess the histologic accuracy of endoscopic biopsy samples of the pineal region. Pineal region tumors usually present with acute hydrocephalus. Histologic diagnosis is paramount, as it greatly influences treatment. Endoscopic techniques can combine histologic diagnosis with relief of the obstructive hydrocephalus in a single operation. Because pineal region tumors can be heterogeneous, initial biopsy samples may not represent the most aggressive portion of the tumor.

METHODS

This retrospective study reviews our experience of endoscopic third ventriculostomy combined with biopsy of the lesion. The histologic diagnosis as a result of the initial biopsy was compared with the final histologic diagnosis to establish the accuracy of the endoscopic biopsy sample in aiding diagnosis.

RESULTS

Forty-seven patients underwent an endoscopic third ventriculostomy. All but 1 patient underwent a concurrent biopsy of the space-occupying lesion and 39 of 46 patients (85%) had a histologic diagnoses. In the remaining 7 patients (15%), the histology was negative; in 6 cases, the second attempt to obtain a histologic diagnosis was successful (2 repeat endoscopic biopsy samples, 2 resections, 2 stereotactic biopsy samples). In 1 patient a presumed low-grade tectal tumor was followed up with sequential scanning. Twenty-eight patients underwent subsequent operations (24 resections, 4 stereotactic biopsies). In 6 of 28 patients (21%), the histologic report was amended after the second procedure.

CONCLUSIONS

The endoscopic biopsy sample yields an accurate histologic diagnosis for most pineal region tumors, with a positive histologic sample in about 85% of patients. However, the results must be interpreted cautiously, as the heterogeneous nature of these tumors may lead to an approximately 21% error rate in the initial tumor diagnosis.