Contributed by Sónia Costa1; Joana Marques2; Pedro Pereira3; Carla Firmo3; José Pimentel3,4
1 Department of Neurology, Hospital Professor Dr. Fernando da Fonseca EPE, Amadora, Portugal
2 Department of Neurology, Instituto Português de Oncologia de Lisboa, Francisco Gentil
3 Laboratory of Neuropathology, Department of Neurology, CHLO, EPE - Hospital de Santa Maria
4 Institute of Molecular Medicine, Faculdade de Medicina de Lisboa
A 23-year-old male with no significant past history, presented with a tonic-clonic generalized seizure. Physical and neurological examinations were normal. MRI of the brain showed a superficial cystic mass with a mural nodule in the right frontoparietal lobe. Patient underwent right frontal craniotomy with total resection of the tumor. The post-operative course was uneventful.
Microscopic examination disclosed a mass lesion composed of two, distinct in origin, cellular components. One was glial, mainly with elongated and spindle-shaped astrocytes, with moderate pleomorphic nuclei (Fig. 1), displaying GFAP immunoreactivity (Fig. 2). The other, neuronal, was composed of mature, with middle pleomorphic nuclei, some times foamy, ganglion neoplastic cells, either intermixed with the glial component (Fig. 3) or clustering in nests (Fig. 4), showing immunoreactivity for neurofilaments (Fig. 5) and synaptophysin (Fig. 6). A dense, prominent, desmoplastic reticulin-rich stroma, intermixed with the neoplastic cells was elicited (Fig. 7). There was no striking nuclear atypia, no necrotic areas, and endothelial proliferation was mild. Mitotic figures were extremely rare, and the proliferation index (Mib-1 immunoreactivity) was below 1%. Despite the presence of some foam cells, there were no true xanthomatous elements. The tumor was partially located in the subarachnoid space, displayed some mononuclear inflammatory perivascular infiltrates and, frequently, there was a clear-cut interface between the tumor and the surrounding brain parenchyma where several microcalcifications (Fig. 8) and Rosenthal fibers were elicited. A striking feature was the presence of a few cells containing brownish-black pigment in the cytoplasm (Fig. 9), as seen by the Fontana-Masson stain (Fig. 10). It stained brown with Fontana-Masson stain, bleached completely with potassium permanganate, and did not stain for either iron (by Perl's stain), neuromelanin or lipofuscin (by periodic acid-Schiff and long Ziehl Neelsen, acid-fast, stains).