Brain Pathology Case of the Month - May 2007

Contributed by Osama M. Al-Agha, MD
Department of Pathology, State University of New York Downstate Medical Center at Brooklyn, Brooklyn, New York 11203


A 15-year-old girl presented to our institution with headache, vomiting, and nausea of 3-week duration. Physical examination showed no focal neurologic deficits. The patient's past medical, surgical, and family histories were all noncontributory.


T1-weighted magnetic resonance imaging (MRI) of the brain showed a cystic mass in the right temporoparietal region measuring 4 x 4 x 4 cm with a well-defined mural nodule measuring 1.5 x 1.5 x 1.5 cm located at the cortical side of the cyst (Fig 1a). The mural nodule enhanced strongly and homogenously following intravenous administration of gadolinium (Fig 1b, 1c).

Intraoperatively, the tumor mass was cystic with a mural nodule attached to the meninges. The mass was totally excised and sent for histopathologic examination. The mural nodule had tan white cut surface with yellow hue. The cyst content was approximately 15 ml of non-bloody fluid which was sent to cytopathologic examination and showed no tumor cells.


On microscopic examination, the tumor consisted of neoplastic astrocytes displaying marked pleomorphism ranging from spindle cells arranged in fascicles with storiform pattern (Fig 2a). intermingled with giant cells with single or multiple atypical, and sometimes bizarre nuclei (Fig 2b, 2c). Cytoplasmic xanthomatous changes were readily seen in many tumor cells (Fig 2d, 2e). Eosinophilic granular bodies were also present throughout the tumor (Fig 2f, Arrows). Patchy lymphocytic infiltrates, mainly perivascular, were present (Fig 2g). Up to 5 mitoses per 10 high power fields were identified (Fig 2h, Arrow). There was no necrosis or microvascular proliferation.

The eosinophilic granular bodies stained positive with Periodic Acid Schiff (PAS) (Fig 3a). A dense reticulin network investing individual tumor cells and occasionally groups of cells was displayed by reticulin stain (Fig 3b). Immunohistochemically, the tumor cells were immunoreactive for GFAP (Fig 3c) with occasional immunoreactivity to neurofilament protein (NFP) antibodies (Fig 3d). No reactivity was detected with epithelial membrane antigen (EMA) antibodies. The maximum Ki-67 labeling index was 3% (Fig 3e).


International Society of Neuropathology