Cytologic characteristics of subependymal giant cell astrocytoma in squash smears: Morphometric comparisons with gemistocytic astrocytoma and giant cell glioblastoma

Objective: To evaluate the squash smear features of subependymal giant cell astrocytoma (SEGA) in comparison with gemistocytic astrocytoma and giant cell glioblastoma. Study Design: We compared the squash smear features of 3 cases of SEGA, 9 cases of gemistocytic astrocytoma and 3 cases of giant cell glioblastoma with the morphometric findings. Results: SEGA had, on average, a 15.84 ± 5.03-μm nucleus, 33.22 ± 12.05-μm cytoplasm and 0.50 ± 0.12 nuclear/cytoplasmic ratio in squash smears. In addition, SEGA showed hairlike processes distributed along the squash direction like strap cells. While the gemistocytic astrocytoma had several tumor cells showing a vertically located nucleus, the tumor cells of SEGA showed nuclei oriented mainly in parallel. Conclusion: These squash cytologic features of SEGA can be very helpful in the differential diagnosis by excluding mimics.