histological appearances cavitron - bmj

J Clin Pathol 1984;37:1101-1104

Histological appearances of intracranial biopsiesobtained using the Cavitron ultrasonic surgicalaspiratorRAS BLACKIE, A GORDON*

From the Department ofPathology, University ofEdinburgh, Edinburgh EH8 9AG, and the*Neuropathology Laboratory, University ofEdinburgh, Western General Hospital, Edinburgh EH4 2XU

SUMMARY The Cavitron ultrasonic surgical aspirator causes localised ultrasonic tissue fragmenta-tion and has recently been used to remove intracranial tumours. We have examined tissuefragments from 17 operations in which the apparatus was used: in all cases a definitive diagnosiscould be made from the material aspirated. This finding has not been previously described.

Prompted by the success of ultrasonic fragmentationand aspiration of cataracts in ophthalmic surgery,the Cavitron ultrasonic surgical aspirator (CUSA)(Cavitron Ultrasonics, Cavitron Corporation, LongIsland City, New York) has been recently intro-duced into neurosurgical practice.'The equipment has been evaluated in animals in a

variety of procedures,2 3 and there are encouragingreports of its use in the treatment of human intra-cranial and intramedullary tumours.45 Becausethere is no mechanical distortion of adjacent tissueand large blood vessels are undamaged, the CUSAhas been used successfully to remove tumours fromsites within the central nervous system where othermethods have proved difficult or carry an unaccept-able risk.

Anticipating that in such circumstances it may bedifficult or impossible to obtain a conventionalbiopsy, we have compared the histology of tissuefragments obtained from the CUSA with theappearances of those obtained by aspiration or exci-sion biopsy.

Patients and methods

PATIENTSTissue fragments were examined from 17 operationson intracranial tumours in which the CUSA wasused in the University of Edinburgh Department ofSurgical Neurology, Western General Hospital. Ineach case a conventional tumour biopsy was

Accepted for publication 4 July 1984

obtained for comparison immediately before the useof the CUSA.

CUSAThe instrument consists of a hollow titanium tubewhich oscillates longitudinally along its axis at a fre-quency of 23 kHz with an amplitude of 0-1 mm.Tissue within 1 to 2 mm of its tip is fragmented. Theoperative field is irrigated with Hartmann's solutionat the rate of 3 to 10 ml/min, and the tissue frag-ments are recovered by a suction device which oper-ates at only 10 to 12 mm Hg. All the aspirated mat-erial is collected into a disposable plastic bottle.At the end of the operation the plastic bottle was

transferred to the laboratory. The top of the bottlewas cut off and material floating on the surface ofthe fluid was discarded; it consisted mainly of airbubbles trapped in fibrin and blood clot. The sedi-ment consisted of isolated, cylindrical pieces oftumour and neural tissue about 1-0 cm long and 0-2cm in diameter. These were washed three times inphysiological saline to remove most of the blood andfibrinous debris, and those fragments which settledto the bottom of the container were fixed in 4%

Tumours examined in the 17 patients

Diagnosis No of cases

Meningioma 3Astrocytoma 6Oligodendroglioma 1Neurilemmoma 2Metastatic carcinoma 4Myxopapillary ependymoma 1

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Fig. 1 Meningioma. Haematoxylin and eosin.Original magnification x 160.

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Fig. 4 Neurilemmoma. Haematoxylin and eosin.Original magnification x 160.

Fig. 2 Perinecrotic pseudopalisading in an astrocytoma.Haematoxylin and eosin. Original magnification x 160.

Fig. 3 Oligodendroglioma. Haematoxylin and eosin.

Original magnification x 160.

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Fig. 5 Metastatic adenocarcinoma. (a) Haematoxylin andeosin. Original magnification x 160.(b) Alcian blue/periodic acid Schiff. Original magnificationb< 160.

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Fig. 6 Myxopapillary ependymoma. Haematoxylinand eosin. Original magnification x 160.

neutral buffered formaldehyde and processed toparaffin wax.

CONVENTIONAL BIOPSIESThese were fixed and processed in an identical fash-ion..-

STAININGSections from all cases were stained with haematoxy-lin and eosin and additional sections from selectedcases were stained with other commonly used spe-cial stains-for example, periodic acid Schiff, phos-photungstic acid haematoxylin, and solochrotnecyanin.

Results

The tumours examined in the 17 patients are listedin the Table.Examples of t-he histological appearances of

CUSA matrial are illustrated in Figs. 1-6.Of the three meningiomas thus treated, two were

-of the transitional variety and one, attached to thefalx, was arachnoidal. The histological appearancesof these three tumours ,were diagnostic; one is illus-trated in Fig. 1. The lobulated arrangement of solidmasses of tumour cells is clearly seen. The con-stituent cells have ill defined cell membranes and thenuclei are pale and round or oval.There were seven gliomas'in the series; six of

them were astrocytomas of varying grades of malig-nancy. Five of the astrocytomas were located in aparietal lobe and all showed prominent vascularendothelial proliferation. Perinecrotic pseudo-palisading could be identified in two CUSA speci-mens (Fig. 2). In one CUSA specimen tumour wasidentified in a Virchow-Robin space, and in anotherthere was,,pronqunced perineuronal infiltration.-A

feature noted in only one specimen was a degree ofartefactual accentuation of microcyst formation.Although two of the astrocytomas showed areas

of oligodendroglial differentiation, there was onlyone pure oligodendroglioma (Fig. 3). Sections of theCUSA material were diagnostic and the round nuc-lei and perinuclear haloes characteristic of thesetumours were clearly seen. An area containingnumerous calcispherules was present in the conven-tional biopsy specimen, but in the CUSA specimenmost of the calcispherules had become separatedfrom the tumocir mass and were concentrated withthe fibrinous debris.Two VIIIth nerve neurilemmomas were aspi-

rated. The material obtained showed the classicappearances of Antoni type B tissue with compactinterlacing bundles of bipolar spindle cells, in whichthere were areas of nuclear palisading. One exampleis illustrated in Fig. 4.Four examples of metastatic carcinoma within the

central nervous system were examined. One eachwas of bronchial, breast, or renal origin, but theprimary site of the fourth tumour remains unknown.Stains for mucin were positive in both the CUSAand conventional biopsy specimens. The Alcianblue/periodic acid Schiff stain from the CUSAspecimen of the metastatic pulmonary adenocar-cinoma is illustrated in Fig. 5(b).

Sections from the biopsies and the CUSA speci-mens of a myxopapillary ependymoma from thecauda equina showed similar histological features.The tumour had a well defined papillary structure ofvascular cores covered by low cuboidal cells withclear cytoplasm (Fig. 6). The prominent vascularcomponent and the recent surgical haemorrhage areevident.

Discussion

The purpose of this study was to determine whethertumour tissue subjected to ultrasonic fragmentationcould be used in diagnostic histopathology. A reviewof the published work showed that this use of theCUSA fragments has not been previously described.Preliminary discussion with the manufacturers sug-gested that this matter had not been explored, butthey had thought that the "disintegration" would beof such magnitude as to give only cellular fragments.

In all the tumours described a definitive diagnosiscould be made using either conventional biopsymaterial or the material aspirated from the CUSA.The quality of the preparations, however, was inseveral cases slightly inferior to that obtained byconventional biopsy. This may be due to a combina-tion of factors, among which the most important is



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probably the inevitable mechanical trauma entailedin shaking the tissue loose. Minor histologicaldeterioration was more apparent in the glialtumours: one notable example was the loss of calci-spherules from the oligodendroglioma. Other diag-nostic features were well preserved, however, and,in the case of microcyst formation, accentuated.On one occasion the CUSA aspirate was stored

overnight at 4°C in Hartmann' s solution. The qualityof preservation and staining was not significantly dif-ferent from that of material prepared immediatelythe specimen was received in the laboratory at theend of the operation. This implies a degree of flexi-bility in the handling procedure, which could, onoccasion, be exploited.Compared with conventional biopsy material, the

best preservation was noted with neurilemmomas,meningiomas, and metastatic carcinomas. Thisfinding may reflect the more physically robust natureof these tumours.

Tissue obtained from the CUSA may representthe bulk of the tumour available. In those caseswhere the initial biopsy is small and has been largelyconsumed in the preparation of smears or cryostatsections, our preliminary findings suggest that valu-

Blackie, Gordon

able diagnostic information may be gained frommaterial which would otherwise have been dis-carded.

References

'Flamm ES, Ranschoff J, Wuchinich D, Broadwin A. Preliminaryexperience with ultrasonic aspiration in neurosurgery.Neurosurgery 1978;2:240-5.

2 Derderian GP, Walshaw R, McGehee J. Ultrasonic surgical dis-section in the dog spleen. Am J Surg 1982;143:269-73.

3Hodgson WJB, Finkelstein JL, Woodriffe P, Jun AHA. Conti-nent anal ileostomy with mucosal proctectomy: a bloodlesstechnique using surgical ultrasonic aspirator in dogs. Br J Surg1979;66:857-60.

4Epstein N, Epstein F, Allen JC, Aleksic D. Intractable facial painassociated with a ganglioglioma of the cervicomedullary junc-tion: report of a case. Neurosurgical Journal 1982; 10:612-6.

5 Epstein F, Epstein N. Surgical management of holocordintramedullary spinal cord astrocytomas in children: report ofthree cases. J Neurosurg 198 1; 54:829-32.

Requests for reprints to: Dr RAS Blackie, Department ofPathology, University Medical School, Teviot Place, Edin-burgh EH8 9AG, Scotland.



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