CLINICAL HISTORY

A 15 year old boy presented to our center with progressive headache, vomiting, gait instability and reduced visual acuity of one month's duration. The patient related a head injury as a result of a fall while playing hockey as coinciding with the onset of his symptoms but no other significant history. Physical examination revealed severe bilateral papilledema.

RADIOLOGY

CT demonstrated marked hydrocephalus involving the lateral and third ventricles. T2 and FLAIR MRI revealed the inferior tectum, aqueduct and superior fourth ventricle to be obliterated by a 1.6 x 1.8 x 2 cm mass and associated 2 x 2 x 2.5 cm cyst. The solid portion displayed minimal enhancement . Imaging features favored an ependymoma or low grade astrocytoma.

MACROSCOPIC DESCRIPTION

Surgical excision of the mass found it to be obstructing the sylvian aqueduct. The grey to tan colored fleshy mass was completely resected from the ventricular system and sent for pathological examination.

MICROSCOPIC DESCRIPTION

Microscopic examination of the resected tumor revealed a highly pleomorphic and fibrillary lesion igures 7 and . Lesional cells varied from pilar to multipolar to giant with multiple and pleomorphic nuclei. Many tumor cells had prominent cytoplasmic vacuolation and/or fine granular brown pigment . Perivascular lymphocytes and sparse eosinophilic granular bodies were present. No mitotic activity, endothelial hyperplasia or necrosis were seen.

The granular brown cytoplasmic pigment stained black with Masson-Fontana preparation . Gomori and Sweet's reticulin stain revealed generous reticulin surrounding individual cells or groups of cells . The neoplastic cells expressed abundant GFAP (Figure 11) and select cells lightly coexpressed synaptophysin and neurofilament. Ki-67 labeling was sparse (below 1% in 10 random fields

DIAGNOSIS PIGMENTED PLEOMORPHIC XANTHOASTROCYTOMA