Cytologic Features of Subependymal Giant Cell Astrocytoma

Abstract

To describe the cytologic features of subependymal giant cell astrocytoma (SEGA) on smears and analyze cytomorphologic parameters that may help in reaching the diagnosis of SEGA.Cytologic smears of 7 cases of SEGA were reviewed and graded semi-quantitatively for 11 cytologic features: clustering, cytoplasmic fibrillary processes (fibrillarity), cellularity, small prominent nudcleoli, binucleation or multinucleation, "strap cells", spindle-shaped cells, mitoses, intranuclear inclusions, nuclear atypia and perivascular palisading/pseudorosettes. Corresponding histologic sections were also reviewed.The study included 5 male and 2 female patients with an average age of 8.3 years (range, 3-16) at surgery. Cytologic examination revealed loosely cohesive clusters of large cells possessing round to oval nuclei with no or minimal atypia; fine, evenly distributed chromatin; and abundant eosinophilic cytoplasm enmeshed in abundant thin, hairlike processes. Predominant features included hypercellularity, cell clustering, and fibrillarity. Binucleation or multinucleation; small, prominent nucleoli; and strap cells were often seen. Although common in histologic sections, perivascular palisading/pseudorosettes and spindled astrocytic cells were rarely noted on smears.The cytologic features of SEGA are highly characteristic and thus are of great use in supporting a diagnosis of SEGA and in excluding mimics, primarily gemistocytic astrocytoma and ependymoma.