Background: Ependymomas constitute 8–10 and 1–3% of central nervous system tumors in children and adults, respectively. Though intraoperative squash smear cytology is well documented, grading is rarely described. Objectives: (1) To assess cytomorphology and grade ependymomas in squash smears. (2) To compare utility of hematoxylin and eosin (H&E) and toluidine blue (TB) staining. Study Design: Ependymomas diagnosed from 2004 to 2010 were retrieved from pathology records. Intraoperative squash smears stained with TB and H&E were studied. Results: Histological sections of 29 ependymomas were graded according to WHO 2007 classification. There were 3 myxopapillary (grade I), 13 grade II, and 13 grade III (anaplastic) ependymomas. Perivascular pseudorosettes were seen in 23 smears, and 11 showed rosettes. Less cohesive cells at the periphery of fragments with unipolar cytoplasmic processes were seen in all smears. The background was fibrillary in all except in myxopapillary ependymoma. Metachromatic material was seen in myxopapillary ependymoma around vessels and in globi. The nucleus was round with stippled chromatin and 1–2 small nucleoli could be seen. All smears of grade III ependymomas showed pleomorphism, mitoses, microvascular proliferation and necrosis. Conclusion: Ependymomas can be diagnosed and graded reliably by squash smear. Myxoid stroma was better appreciated by TB staining. TB and H&E complement each other in squash smears for cytomorphology.

1.
Fokes EC Jr, Earle KM: Ependymomas: clinical and pathological aspects. J Neurosurg1969;30:585–594.
2.
Wiestler OD, Schiffer D, Coons S, et al: Ependymoma; in Kleihues P, Cavenee WK (eds): World Health Organization Classification of Tumors. Pathology and Genetics of Tumors of the Nervous System. Lyon, IARC Press, 2000, pp 72–76.
3.
Firlik K, Martinez J, Lunsford DL: Use of cytological preparations for the diagnosis of stereotactically obtained brain biopsies: a 19-year experience and survey of neuropathologists. J Neurosurg 1999;91:454–458.
4.
Roessler K, Dietrich W, Kitz K: High diagnostic accuracy of cytologic smears of central nervous system tumors. Acta Cytol 2002;49:664–667.
5.
Shah AB, Muzumdar GA, Chitale AR, Bhagwati SN: Squash preparation and frozen section in intraoperative diagnosis of central nervous system tumors. Acta Cytol 1998;42:1149–1154.
6.
Asha T, Shankar SK, Rao TV, Das S: Role of squash smear technique for rapid diagnosis of neurosurgical biopsies – a cytomorphological evaluation. Indian J Pathol Microbiol 1989;32:152–160.
7.
Barnard RO: Smear preparations in the diagnosis of malignant lesions of the central nervous system; in Koss LG, Coleman DV (eds): Advances in Clinical Cytology. London, Butterworth, 1981, pp 254–269.
8.
Torres BLF, de Noronha L, Gugelmin E, et al: Accuracy of smear technique in cytological diagnosis of 650 lesions of central nervous system. Diagn Cytopathol 2001;24:293–295.
9.
Moss TH, Nicoll JAR, Ironside JW: Intraoperative diagnosis in neurosurgical practice; in Moss TH, Nicoll JAR, Ironside JW (eds): Intraoperative Diagnosis CNS Tumors. London, Arnold Press, 1997, pp 1–5.
10.
Tihan T, Zhou T, Holmes E:The prognostic value of histological grading of posterior fossa ependymomas in children: a Children’s Oncology Group study and a review of prognostic factors.Mod Pathol 2008;21:165–177.
11.
Prayson RA: Clinicopathological study of 61 patients with ependymoma including MIB 1 immunohistochemistry. Ann Diagn Pathol 1999;3:11–18.
12.
Kawano N, Yasui Y, Utsuki S, et al: Light microscopic demonstration of the microlumen of ependymoma: a study of usefulness of antigen retrieval of epithelial membrane antigen (EMA) staining. Brain Tumor Pathol 2004;21:17–21.
13.
Ng HK: Cytologic features of ependymomas on smear preparations. Cytology 1994;38:331–334.
14.
Zhang YX, Luo KS, Liv JC, et al: Cytological diagnosis of 500 cases of intracranial tumors during craniotomy. China J Clin Cytol 1987;3:19–27.
15.
Takei H, Kosarac O, Powell SZ: Cytomorphologic features of myxopapillary ependymoma: a review of 13 cases. Acta Cytol 2009;53:297–302.
16.
Kumar PV: Nuclear grooves in ependymoma. Cytologic study of 21 cases. Acta Cytol 1997;41:1726–1731.
17.
Kim NR, Chung D, Lee SK: Intramedullary clear cell ependymoma in the thoracic spinal cord: a case with its crush smear and ultrastructural findings. J Korean Med Sci 2007;22(suppl):149–153.
18.
Otani M, Fujita K, Yokoyama A, et al: Imprint cytologic features of intracytoplasmic lumina in ependymoma. A report of two cases. Acta Cytol 2001;45:430–434.
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