DIAGNOSTIC DILEMMASSection Editor: Claire W. Michael, M.D.

Crush Preparations ofMeningiomas:Can Grading Be Accomplished?Sarfraz Ali, M.D.,1 Aziza Nassar, M.D., F.I.A.C.,2

and Momin T. Siddiqui, M.D., F.I.A.C.3*

Crush preparations (CP) for the diagnosis of meningioma areroutinely performed in the frozen section suite when tissue is sub-mitted for intraoperative consultation. The goal of this study wasto examine the cytologic features of meningiomas in CP and eval-uate if benign meningioma (Grade 1), atypical meningioma(Grade 2), and malignant meningioma (Grade 3) can be diag-nosed on CP. All cases of meningioma (1999–2007), which weresubmitted for frozen section at our institution, were retrospec-tively reviewed. These cases were examined intraoperatively byfrozen section and CP. The final histologic diagnosis was takenas the gold standard. A total of 107 meningiomas cases werereviewed. The cytological features of all these cases were studied,and features such as pleomorphism, hemorrhage, necrosis, mito-sis, and presence or absence of nucleoli were recorded. Using thefinal histopathologic diagnosis as the gold standard, there were72 (Grade 1), 22 (Grade 2), and 13 (Grade 3) meningioma cases,which were studied. In conclusion, this study reviews the salientcytologic features of Grades 1–3 meningiomas. It demonstratesthat it is difficult to separate Grade 1 from Grade-2 meningiomaon CP, and last, Grade-3 meningioma can be easily diagnosed onCP. Diagn. Cytopathol. 2008;36:827–831. ' 2008 Wiley-Liss, Inc.

Key Words: meningioma grading; crush preparation cytology

Meningiomas arise from the cells of the arachnoidal lining

or meningothelial cells. These are commonly found in

association with arachnoid villi at the dural venous sinuses

and veins.1,2 Meningiomas account for 30% of all primary

brain tumor diagnoses in adults in the United States.3

These lesions can occur in people of any age but com-

monly present in middle age. Women are more likely to

develop a meningioma, with a female/male ratio of *2:1

intracranially and 10:1 in the spine.4 Ninety percent of all

meningiomas occur in the supratentorial compartment.5,6

Histologically and cytologically, meningiomas represent

a strikingly heterogeneous group of neoplasms. They have

been subdivided into a variety of types, including meningo-

theliomatous, fibrous, transitional, psammomatous, and

angiomatous, among others. About 85% of meningiomas

are benign (Grade I), whereas 10% are atypical (Grade II)

and 3–5% are malignant (anaplastic, Grade III).7 Crush

preparation (CP) for the diagnosis of meningioma are rou-

tinely performed in the frozen section suite when small tis-

sue samples are submitted for intraoperative consultation.

The goal of this study was to examine the cytologic features

of meningiomas in CP and evaluate if benign, atypical, and

malignant meningioma can be diagnosed on CP, alone.

Materials and Methods

All cases of meningioma from 1999 to 2007, an 8-year

period, were submitted for frozen section at our institution

were retrospectively reviewed. A total of 107 meningioma

cases were reviewed in our study. All cases were exam-

ined intraoperatively by frozen section and CP. The tumor

samples were obtained by either using biopsy forceps or

surgical resection. These samples were placed in normal

saline and submitted to the frozen section laboratory for a

diagnosis. Approximately 1–2-mm diameter tissue frag-

ment from each specimen was gently crushed between

two glass slides. The smears were then prepared by using

both, 95% ethanol-fixed slides, which were stained with

hematoxylin and eosin, as well as air drying and staining

by Diff-Quik technique.

1Department of Pathology and Laboratory Medicine, Emory UniversityHospital, Atlanta, Georgia

2Department of Pathology, Mayo Clinic, Rochester, Minnesota3Department of Pathology and Laboratory Medicine, Emory University

Hospital, Atlanta, Georgia*Correspondence to: Momin T. Siddiqui, M.D., F.I.A.C., Emory Uni-

versity Hospital, Department of Pathology and Laboratory Medicine,1364 Clifton Road, NE, Atlanta, GA 30322. E-mail: mtsiddi@emory.edu

Received 21 May 2008; Accepted 20 June 2008DOI 10.1002/dc.20929Published online in Wiley InterScience (www.interscience.wiley.com).

' 2008 WILEY-LISS, INC. Diagnostic Cytopathology, Vol 36, No 11 827

Results

A total of 107 meningioma cases were studied. The loca-

tions of these tumors varied and are summarized in Table I.

The final diagnosis of these cases showed that 72 cases

were of Grade I, 22 were of Grade II, and 13 cases were

of Grade III. Mitotic activity on the CP was specifically

studied in detail and given a score ranging from 0 to 2 (0,

no mitotic activity observed; 1, 1–19 mitotic figures per

10 HPF; and 2, 20 or more mitotic figures per 10 HPF).

The salient cytological features of all three Grades of me-

ningioma were reviewed on CP and are summarized in

Table II. Grade I: the smears were hypercellular (72 of

72 cases). There were syncitial large tissue fragments,

arranged as clusters, whorls, or sheets (72 of 72 cases) as

shown in Figure 1. Papillary configuration were also

noted (29 of 72 cases) as shown in Figure 2. The cells

within these tissue fragments were polygonal to spindle

with eosinophilic and wispy cytoplasm (72 of 72 cases).

Nuclei were oval, sharply outlined, and slightly eccentric

(72 of 72 cases). Nuclear chromatin was homogeneous

and evenly distributed (72 of 72 cases). Small centrally

placed nucleoli were also present (68 of 72 cases). Nu-

clear grooves and cytoplasmic pseudoinclusions were also

identified (42 of 72 cases). Single polygonal and spindle

cells with wispy cytoplasmic prolongations were also

present in the background (70 of 72 cases). Scattered na-

ked nuclei were also observed in the background (62 of

72 cases). Mitotic activity was scored 0 in all cases. Kar-

yorrhexis and necrosis were also absent (0 of 72 cases).

Grade II: the smears were hypercellular with a prominent

sheet like architecture with whorls and clusters (22 of

22 cases) as shown in Figure 3. The cells were polygonal

with scant cytoplasm, which was wispy and granular (21

of 22 cases). The nuclei were slightly eccentric and

showed slight pleomorphism (19 of 22 cases). The nucle-

oli were central and large (18 of 22 cases). Mitotic activ-

ity was also seen in two (scored as 1 in first case and 2 in

the second case) of 22 cases. No evidence of necrosis

was identified in any case (0 of 22 cases). Single cells as

well as naked nuclei were also seen (9 of 22 cases). Nu-

clear grooves and nuclear pseudoinclusions were also

present (12 of 22 cases). Grade III: the smears were

hypercellular (13 of 13 cases). Clusters and whorls of

pleomorphic cells as well as single cells were present (13

of 13 cases). The cells had scant cytoplasm and a high

nucleus to cytoplasmic ratio (12 of 13 cases) as shown in

Figure 4. Prominent nucleoli were also commonly identi-

fied (11 of 13 cases). Mitotic activity was very frequent

in 10 (scored as 1 in one case and 2 in the remaining

9 cases) of 13 cases. Hemorrhage and necrosis were also

present (11 of 13 cases).

Discussion

Meningioma is one of the most common primary tumors

of the central nervous system. They are generally slow-

growing tumors and may be found very infrequently in

ectopic locations.8,9 They account for 13–26% of all pri-

mary intracranial tumors with an annual incidence rate

of *6/100,000 population.10 Meningiomas rarely meta-

stasize, which occurs in less than 1% of cases.11 Local

recurrence is a major cause of complications and death

in meningiomas.12 Metastasis often occurs only after the

local control has been lost.13 On the other hand, there

have been examples of ‘‘benign metastasizing meningio-

mas’’ with Grade I histologic characteristics and an indo-

lent clinical course.11,14,15 In view of these findings, it

has been suggested that the histological characteristics

and Grade of the metastatic tumor, rather than the fact

that there is metastatic disease, may be more pertinent to

the clinical outcome. Thus, histological grade is impor-

tant to determine clinical outcome when considering

meningiomas.

The aim of our study was to assess the usefulness and

accuracy of cytologic smears by making CP for grading

meningiomas. CP is commonly used for diagnosing neu-

ropathologic specimens intraoperatively. Shukla et al.16 in

their study include 278 patients with central nervous sys-

tem tumors, for whom CP was used. Two forty-four of

278 patients showed correlation with final histological di-

agnosis, giving the diagnostic accuracy of 87.76% for

usage of CP, in their study. Also, it needs to be men-

tioned that CP is almost always used as an add-on to fro-

zen sections, unless the submitted material is very limited,

when only a CP may be prepared from the limited tissue.

Numerous reports describing cytologic features of me-

ningioma have been published in the literature.17–19 In

our study, 107 meningioma cases were reviewed to assess

the cytologic features of meningiomas to assess for grad-

ing purposes. In all the cases, CPs were made and cyto-

logic diagnosis was correlated with final histologic diag-

nosis. Grade-I meningioma is usually easy to recognize

cytologically on CP.17–19 The key features seen in Grade-

I meningiomas in our study were hypercellularity without

evidence of necrosis. Mitotic activity was also scored as 0

(Fig. 1). The cells within these tissue fragments were po-

lygonal with eosinophilic cytoplasm. The nuclei were

oval with small central nucleoli. Numerous single cells in

the background were also present, which were mostly po-

lygonal with wispy cytoplasmic prolongations. Very often,

the cytoplasmic prolongations were of fibrillary quality. A

few of these single cells had hyperchromatic nuclei.

Table I. Distribution of Meningiomas in Various Body Locations

Location of tumor No. of cases % of total

Intracranial meningioma 92 85.9Spinal cord meningioma 11 10.2Orbital meningioma 3 2.8Olfactory groove meningioma 1 0.93

ALI ET AL.

828 Diagnostic Cytopathology, Vol 36, No 11

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Table II. Salient Cytological Features of Meningioma

Cytologic features of meningioma Grade I Grade II Grade III

Cellular architectureCellularity Hypercellular Hypercellular HypercellularCell shape Polygonal to spindle Polygonal PleomorphicMitotic activity No mitotic activity (score ¼ 0) Mitotic activity in few

cells (score ¼ 1 to 2)Mitotic activity very frequent(score ¼ 2, rarely 1)

Necrosis No necrosis No necrosis Frequent necrosisCytoplasm

Cytoplasmic pattern Eosinophilic Granular ScantNucleus

Shape Oval Pleomorphic PleomorphicNucleolus Small central Large eccentric Prominent

Comparison of cytologic features of Grades I–III.

Fig. 1. CP of a Grade I meningioma showing whorls with polygonalcells with intranuclear inclusions and abundant eosinophilic cytoplasm(H&E 340). [Color figure can be viewed in the online issue, which isavailable at www.interscience.wiley.com.]

Fig. 2. Grade I meningioma showing a papillary configuration with pali-sading nuclei, some of which are naked (H&E 340). [Color figure canbe viewed in the online issue, which is available at www.interscience.wiley.com.]

Fig. 3. CP of a Grade II meningioma with hypercellular smear withclusters of cells showing mild to moderate degree of nuclear pleomor-phism (H&E 360). [Color figure can be viewed in the online issue,which is available at www.interscience.wiley.com.]

Fig. 4. Grade III meningioma with necrosis and abundant pleomorphiccells dispersed singly (H&E 360). [Color figure can be viewed in theonline issue, which is available at www.interscience.wiley.com.]

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Diagnostic Cytopathology DOI 10.1002/dc

Papillary configurations (29 of 72 cases) and cytoplasmic

pseudoinclusions along with nuclear grooves (42 of

72 cases) were also identified in Grade-I meningiomas

(Fig. 2). These papillary configurations and cytoplasmic

pseudoinclusions can pose a possible pitfall, because

they have also been found in other tumors, including

papillary carcinoma of the thyroid.20 Cellular whorls

were also seen in Grade-I meningiomas in our study

(66 of 72 cases). These are a common cytologic feature

in Grade-I meningiomas, and sometimes can be confused

with the keratin pearls commonly seen in squamous cell

carcinomas and may also pose as a possible pitfall in

diagnosis.21

Grade-II meningiomas also exhibited hypercellularity,

and large tissue fragments were noted on CP. The cells

were arranged as whorls and clusters (22 of 22 cases).

Papillary configurations were virtually absent in Grade-II

meningiomas. The cells were polygonal with slightly less

cytoplasm when compared with Grade I. The cytoplasm

in Grade-II lesions was somewhat wispy and granular (21

of 22 cases) in contrast to the eosinophilic cytoplasm

seen in Grade I (Fig. 3). The nuclei in Grade II were also

slightly larger, and more eccentrically placed, than those

seen in Grade I. Slight pleomorphism of nuclei was also

more apparent in Grade II (19 of 22 cases). Nuclear

grooves and pseudoinclusions were also present in Grade

II (12 of 22 cases). The nucleoli were more centrally

placed and slightly larger than those seen in Grade I (18 of

22 cases). However, smaller nucleoli in a cellular group

were noted in all cases of Grade II. Single intact tumor

cells as well as naked nuclei were also present in Grade II;

however, these were seen in fewer cases when compared

with Grade-I meningiomas. Mitotic activity was observed

in only 2 of the 22 Grade-II cases and given a score of 1

and 2, respectively, for the two cases. This was helpful in

differentiating Grade II from Grade-1 cases, where the

cases reviewed each had a score of 0 for mitotic activity.

No necrosis was identified in any of the Grade-II cases,

which was found to be similar to Grade-I CP.

Grade-III meningiomas share some cytological features

with Grade-II meningiomas, such as hypercellularity, mi-

totic activity, and pleomorphic nuclei with large promi-

nent nucleoli.

The cells were pleomorphic and clearly malignant

appearing in all Grade-III CP that were reviewed in our

study (Fig. 4). These cases were relatively easier to iden-

tify on CP alone, because mitotic activity was very com-

mon. In 10 of 13 cases, mitotic activity was noted, and of

these 10 cases, only one case had a score of 1, whereas

the remaining 9 had a score of 2. Hemorrhage and necro-

sis were additionally noted in 11 of 13 cases. However,

the main overlapping cytologic features with Grade-II me-

ningiomas were the tumor cells, which were also polygo-

nal, and showed a large nucleus with scant cytoplasm.

The above review of cytologic features of Grades I–III

would be very helpful in grading meningiomas on CP.

However, in clinical practice, potential errors in grading

due to the process of embolization may be encountered.

Embolization of meningiomas is used sometimes preoper-

atively to minimize intraoperative bleeding. Embolization

brings on some histological changes that may lead to

overgrading the tumor, including macronucleoli, necrosis,

and compensatory proliferation with increased numbers of

mitotic figures.22–24 Communication between the neuro-

surgeon and neuropathologist regarding the use of emboli-

zation can reduce the risk of overgrading. Similarly,

knowledge of the patient’s history of radiation therapy

will prevent undue concern over necrosis or cellular

atypia.

In the past 5–10 years, there has been a considerable

progress in the understanding of the biology of meningi-

oma. The concept of prognosis and recurrence of manin-

gioma are a subject of great significance. Several markers

can actually be used as prognostic indicators in meningio-

mas and may allow a more individualized management of

patients. Two of the most important factors that determine

the prognosis in patients with meningioma are the extent

of the resection and the tumor’s histological Grade.

Higher grade meningiomas are more likely not to receive

a gross total resection, and even when they do, there may

still be recurrence.25,26 As an example, the authors of one

study found that within 5 years of resection, 12% of be-

nign meningiomas recurred compared with 41% of Grade-

II tumors.27 In another study, atypical meningioma (Grade

II) displayed a significant 10-year recurrence rate of 66%,

compared with 2% for a benign meningioma (Grade I).28

Once a tumor recurs, it is more likely to do so again, ulti-

mately leading to a loss of local control and rarely, me-

tastasis.29 Investigators at the Mayo Clinic have partially

dealt with these problems by clarifying the significance of

brain invasion and developing objective criteria that

allows reproducible grading of meningiomas, histologi-

cally. The investigators examined the correlation between

numerous parameters that include various histological fea-

tures (mitotic figures, sheeting, prominent nucleoli, hyper-

cellularity, and formation of small cells), brain invasion,

and progression-free survival.14,27 A few studies have

focused on minimal cytological details such as excessive

mitotic activity (20 or more mitotic figures per 10 HPF)

and anaplasia to be presumed as important prognostic cri-

teria.14,30 These details can also help in evaluating the CP

of meningiomas, especially in very small samples.

The revised and updated WHO classification is also a

major innovation in the histopathology of meningiomas.

This allows one to make a better assessment of the recur-

rence and infiltrative behavior of these tumors.31 This text

can be used for future studies with larger case numbers

for elaborating on the cytologic features of meningiomas.

ALI ET AL.

830 Diagnostic Cytopathology, Vol 36, No 11

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In conclusion, it is possible to diagnose these tumors by

using CP. The grading can also be accomplished if partic-

ular attention is paid to the distinguishing cytomorpholog-

ical features in correlation with clinic radiological find-

ings and cytochemistry. It should be borne in mind that

on CP alone, there may be a considerable overlap in the

features seen in Grades I and II. However, Grade III may

be the easiest to diagnose on CP alone. Scoring mitotic

activity may also may helpful, which we, in our study,

found to be low (0) for Grade-I cases and high (predomi-

nantly 2) for Grade-III cases. Additional studies powered

by a higher number of cases that include clinical follow-

up data are needed to achieve a better understanding of

the subject. Furthermore, these data may improve our

ability to devise new therapeutic targets for the eradica-

tion of aggressive meningiomas.

References

1. De Monte F. Current management of meningiomas. Oncology

(Williston Park) 1995;9:83–91;96:99–101.

2. Wilson CB. Meningiomas: Genetics, malignancy, and the role of

radiation in induction and treatment. The Richard C. Schneider Lec-ture. J Neurosurg 1994;81:666–675.

3. CBTRUS: Statistical Report: Primary Brain Tumors in the United

States, 1998–2002. Chicago: Central Brain Tumor Registry of theUnited States, 2005.

4. Commins DL, Atkinson RD, Burnett ME. Review of meningioma

histopathology. Neurosurg Focus 2007;23:E3.

5. Bondy M, Ligon BL. Epidemiology and etiology of intracranial me-

ningiomas: A review. J Neurooncol 1996;29:197–205.

6. Sanson M, Cornu P. Biology of meningiomas. Acta Neurochir

(Wein) 2000;142:493–505.

7. Louis DN, Scheithauer BW, Budka H, et al. Pathology and genetics

of tumours of the nervous system. In: Kleihues P, Cavenee WK,editors. World Health Organization Classification of Tumours.Lyon, France: IARC Press; 2000. p 176–184.

8. Baisden BL, Hamper UM, Ali SZ. Metastatic meningioma in fine

needle aspiration (FNA) of the lung: Cytomorphologic finding.Diagn Cytopathol 1999;20:291–294.

9. Kalfa M, Daskalopoulou D, Markidou S. Fine needle aspiration

(FNA) biopsy primary cutaneous meningioma: Report of two cases.Cytopathology 1999;10:54–60.

10. Longstreth WT, Dennis LK, McGuire VM, et al. Epidemiology ofintracranial meningiomas. Cancer 1993;72:639–648.

11. Gladin CR, Salsano E, Menghi F, et al. Loss of heterozygosity stud-ies in extracranial metastatic meningiomas. J Neurooncol 2007;85:81–85.

12. Dziuk TW, Woo S, Butler EB, et al. Malignant meningioma: An in-dication for initial aggressive surgery and adjuvant radiotherapy.J Neurooncol 1998;37:177–188.

13. Hug EB, Devries A, Thornton AF, et al. Management of atypicaland malignant meningiomas: Role of high-dose, 3D-conformal radi-ation therapy. J Neurooncol 2000;48:151–160.

14. Perry A, Scheithauer BW, Stafford SL, Lohse CM, Wollan PC.‘‘Malignancy’’ in meningiomas: A clinicopathologic study of 116patients, with grading implications. Cancer 1999;85:2046–2056.

15. Ng TH, Wong MP, Chan KW. Benign metastasizing meningioma.Clin Neurol Neurosurg 1990;92:152–154.

16. Shukla K, Parikh B, Shukla J, Trivedi P, Shah B. Accuracy of cyto-logic diagnosis of central nervous system tumours in crush prepara-tion. Indian J Pathol Microbiol 2006;49:483–486.

17. Sidawy MK, Jannotta FS. Intraoperative cytologic diagnosis oflesions of the central nervous system. Am J Clin Pathol 1997;108:56–66.

18. Kobayashi S. Meningioma, neurilemmoma and astrocytoma speci-mens obtained with the squash method for cytodiagnosis. A cyto-logic and immunochemical study. Acta Cytol 1993;37:913–922.

19. Siddiqui MT, Mahon BM, Cochran E, Gattuso P. Cytologic featuresof meningiomas on crush preparations: A review. Diagn Cytopathol2008;36:202–206.

20. Solares J, Lacruz C. Fine needle aspiration cytology diagnosis of anextracranial meningioma presenting as a cervical mass. Acta Cytol1987;31:502–504.

21. Kepes JJ. Cellular whorls in brain tumors other than meningiomas.Cancer 1976;37:2232–2237.

22. Ng HK, Poon WS, Goh K, Chan MS. Histopathology of post-embo-lized meningiomas. Am J Surg Pathol 1996;20:1224–1230.

23. Patsouris E, Laas R, Hagel C, Stavrou D. Increased proliferative ac-tivity due to necroses induced by pre-operative embolization in be-nign meningiomas. J Neurooncol 1998;40:257–264.

24. Perry A, Chicoine MR, Filiput E, Miller JP, Cross DT. Clinicopath-ologic assessment and grading of embolized meningiomas: A correl-ative study of 64 patients. Cancer 2001;92:701–711.

25. Goel A, Muzumdar D, Desai KI. Tuberculum sellae meningioma: Areport on management on the basis of a surgical experience with70 patients. Neurosurgery 2002;51:1358–1364.

26. Perry A, Giannini C, Raghavan R, et al. Aggressive phenotypic andgenotypic features in pediatric and NF2-associated meningiomas: Aclinicopathologic study of 53 cases. J Neuropathol Exp Neurol2001;60:994–1003.

27. Perry A, Stafford SL, Scheithauer BW, Suman VJ, Lohse CM. Me-ningioma grading: An analysis of histologic parameters. Am J SurgPathol 1997;21:1455–1465.

28. Mahmood A, Caccamo DV, Tomecek FJ, Malik GM. Atypical andmalignant meningiomas: A clinicopathologic review. J Neurosurg1993;33:955–963.

29. Goyal LK, Suh JH, Mohan DS, Prayson RA, Lee J, Barnett GH.Local control and overall survival in atypical meningioma: A retro-spective study. Int J Radiat Oncol Biol Phys 2000;46:57–61.

30. Fabiani A, Trebini F, Favero M, Peres B, Palmucci L. The signifi-cance of atypical mitoses in malignant meningiomas. Acta Neuropa-thol 1977;38:229–231.

31. Perry A, Louis DN, Scheithauer BW, Budka H, von Diemling A.Meningiomas. In: Louis DN, Ohgaki H, Wiestler OD, et al., editors.World Health Organization Classification of Tumours of the CentralNervous System. 4th ed. Lyon: IARC; 2007. p 164–172.

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