Cytologic features of subependymal giant cell astrocytoma: A review of 7 cases

Objective: 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. Study Design: Cytologic smears of 1 cases of SEGA were reviewed and graded semi-quantitatively for 11 cytologic features: clustering, cytoplasmic fibrillary processes (fibrillarity), cellularity, small prominent nucleoli, binucleation or multinucleation, "strap cells," spindle-shaped cells, mitoses, intranuclear inclusions, nuclear atypia and perivascular palisading/pseudorosettes. Corresponding histologic sections were also reviewed. Results: 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. Conclusion: 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.