The patient went on to have a resection.

Histology

Sections show pieces of a somewhat circumscribed tumor composed of abundant small thin-walled capillary sized blood vessels. The intervening stroma contains epithelioid-to-stellate cells with bland nuclei and vacuolated cytoplasm. There is no necrosis, mitoses or atypia seen. A piece of the cerebellum is also included in the biopsy.

IMMUNOHISTOCHEMISTRY: The tumor cells stain positively in a patchy distribution for inhibin. The tumor cells are negative for Cam5.2 and Pax8.

FINAL DIAGNOSIS: hemangioblastoma (WHO Grade I).

Discussion

The intercanalicular lesion has been followed and has not significantly changed in size. At this stage, it is presumed to be a schwannoma although the simultaneous diagnosis is unnerving.