British Journal of Ophthalmology, 1987, 71, 858-863

Retinoblastoma: report of a case with minimal retinalinvolvement but massive anterior segment spreadALEC GARNER,' JACK J KANSKI,2 AND FIONA KINNEAR2

From the 'Department ofPathology, Institute of Ophthalmology, University ofLondon, and the 2King EdwardVII Hospital, Windsor

SUMMARY The case is described of a unilateral retinoblastoma in a 7-year-old girl which wasinitially misdiagnosed because of massive anterior segment involvement in the apparent absence ofa retinal lesion. Only on histopathological examination of the enucleated eye was the presence ofretinal tumour established, this being confined to two minute foci at the extreme periphery.

Invasion of the anterior segment by retinoblastoma isa well recognised if not very common complication,and in that it may simulate ocular inflammation it is asignificant source of misdiagnosis. 2 Seeding from anendophytic tumour is the usual cause of such spread,but appreciation of the true nature of the diseaseprocess can be difficult if associated cataract forma-tion or vitreous exudates interfere with examinationof the posterior segment. Nevertheless, given aproper index of suspicion, recourse to alternativemethods of investigation such as ultrasonographyand CT scanning should lead to the correct diagnosis.More difficult is the much rarer diffuse infiltratinggrowth pattern,' I since the retina may appear clinic-ally normal despite adequate visualisation.

In this report we describe a child with massiveanterior segment invasion in which the retinalinvolvement was confined to two minute foci at theextreme periphery. The paucity of retinal involve-ment is unprecedented in our experience of over 1000retinoblastoma cases and we know of only one othercase in the literature to invite comparison.5

Case history

A 7-year-old girl presented in March 1985 complain-ing of redness and blurring of vision of her right eyefor about four weeks. On examination visual acuitywas reduced to 6/60. Slit-lamp biomicroscopy showeda severe anterior uveitis with large iris nodules (Fig.1) and cells and opacities in the anterior vitreous.Investigations, all of which were negative, included a

Correspondence to Professor A Garner, Institute of Ophthal-mology, 17/25 Cayton Street, London EC1V 9AT.

full blood count, plasma viscosity, toxoplasma dyetest, and conjunctival biopsy for sarcoidosis. Apresumptive diagnosis of granulomatous uveitis wasmade, and treatment was begun with intensivetopical corticosteroids and systemic prednisolone5 mg three times a day. Subsequently the intraocularpressure became raised to 44 mmHg, and because itfailed to respond to antiglaucoma therapy withtimoptol 0 25% twice daily, propine 0-1% twicedaily, and acetazolamide 125 mg four times a day acyclocryotherapy operation was performed at theend of May 1985.The intraocular inflammation remained extremely

active despite an anterior sub-Tenon's capsule injec-tion of methylprednisolone (Depomedrone). In earlyJune 1985 a blood stained hypopyon developed (Fig.2) and the lens became cataractous. At the end ofJune 1985 it was suspected that the eye might be

Fig. I NIotidlarintf0tratlot of the iris by retinoblastoma.858

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Retinoblastoma: report ofa case with minimal retinal involvement but massive anterior segment spread

Fig. 2 Bloodstainedpseudohypopyon in conjunction withretinoblastoma andsecondary cataract.

harbouring a malignant tumour, and diagnosticaspirates were taken from the aqueous humour andanterior vitreous. At the same time the iris was

biopsied and the lens excised with a vitreous cutterthrough a pars plana incision. After the lens wasremoved a mass of white friable tissue was found inthe area of the inferior pars plana. Following apreliminary histological report which suggested thepresence of a malignant tumour an enucleation wasperformed two weeks later.

In February 1986 the prosthesis became tiltedowing to an orbital swelling which quickly developedinto an expanding orbital mass. In mid March 1986 anexcision biopsy of the mass was performed andhistology showed recurrence of the tumour. Thepatient was treated by orbital radiotherapy andadjuvant chemotherapy. Staging investigations priorto the institution of chemotherapy showed no

Fig. 3 Aqueous tap showing cells with small, darkly stainednuclei and scanty cytoplasm. Some cells are separate, othersare in clumps and many are degenerate. Haematoxylin andeosin.

evidence of gross metastatic disease, but monoclonalantibodies on the bone marrow aspirate did show afew cells positive for neuroectodermal markerssuggesting possible infiltration of her bone marrowwith retinoblastoma cells which were not identifiableon standard light microscopy. Following completionof the initial course of chemotherapy the marrowaspirate was negative for cells of neuroectodermalorigin on monoclonal antibody studies. Since thenthe patient has received two further courses ofchemotherapy and is due to have more. In June 1986she was alive and well, with no sign of furtherrecurrence.

PATHO LOGYInitial biopsies. A piece of iris removed at the timeof lensectomy showed the stroma to be replacedalmost completely by cells that were mostly roundwith quite strongly basophilic nuclei and hardly anycytoplasm. Some nuclear pyknosis and karyorrhexiswere also seen. Samples from the aqueous (Fig. 3)and vitreous humours contained similiar cells, lyingboth singly and in clumps, and some haemorrhage.Immunohistochemical staining by a peroxidase-antiperoxidase method gave negative responses forcell-bound immunoglobulin using a polyvalent anti-serum, for S-100 protein, and for y-neuron-specificenolase. Despite the lack of confirmatory evidencefrom the marker studies of a neuronal derivation atentative diagnosis of retinoblastoma was made.

Enucleation specimen. There was evidence of arecent superior iridectomy, and the residual iris hadan uneven, nodular, and greyish white appearance.Opening the globe in a vertical plane and removingthe nasal calotte revealed soft, creamy nodulescovering much of the posterior surface of the iris andsimilar material overlying the ciliary body. A littlehaemorrhage was observed on the posterior retinalsurface and in the anterior vitreous, but otherwise theretina showed no further abnormality on macro-scopical examination.

Light microscopy showed that most of the irisstroma and much of the ciliary body was infiltratedand replaced by round cells comparable to those seenin the earlier biopsy (Fig. 4). In places, particularlywithin the ciliary body, there was a tendency for thecells to form cords or ribbons, but true Flexner-Wintersteiner rosettes were not seen (Fig. 5). Therewere numerous islands of similar cells within theposterior chamber and in the anterior chamber,where they also lined the back of the cornea andoccluded the drainage angle. The cells at the centre ofsome of the larger clumps were necrotic. Sectionspassing through the site of surgical interventionshowed tumour cells in proximity to the scleralincision, but there was no sign of extraocular tumour.

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Alec Garner, Jack J Kanski, and Fiona Kinnear

Fig. 4 Section ofthe enucleatedeye showing massive infiltration ofthe iris by small, darkly stainedtumour cells. Free lying tumourcells in the aqueous, somehaemorrhage and a remnant oflensare also seen. Haematoxylin andeosin.

The lens capsule with some residual lens material wasadherent to the pupillary margin of the iris, and therewas blood in the anterior vitreous. Some atrophy ofthe corneal epithelium, possibly reflecting the effectsof raised intraocular pressure, was also seen. Initialsections of the retina revealed no abnormality (Fig.6) and it was only after examining multiple levels thattwo small, discrete foci of cellular proliferationcomparable to that seen in the anterior segment wereidentified between the 11 and 12 o'clock meridiansand the 6 and 7 o'clock meridians respectively at theextreme periphery (Figs. 7, 8). Neither focus wasmore than 1.5 mm in diameter, and there wasminimal thickening of the affected retina. Theinferior tumour proliferation was separated from the

Fig.5 Tumourcellsintheciliary ; ' t:body areforming cords, while those 4 aon its surface are randomly Xarranged with little evidence ofrosetteformation. Haematoxylin tah7and eosin. I I

pars plana ciliaris by about 1*0 mm of atrophic,acellular retina. Origin of the neoplastic process fromthe bipolar cell layer appeared possible. Away fromthe tumour the retina appeared to be normal, as didthe optic nerve and choroid.

Immunohistochemistry on paraffin embeddedtissue gave a variable but, in places, unmistakeablestaining response for y-neuron-specific enolase.Reactions for S-100 protein and glial fibrillary acidicprotein were negative.Examination of formalin fixed, free lying cells

recovered from the posterior chamber by transmis-sion electron microscopy revealed occasional cilia-like structures with a ring of nine doublet micro-tubular structures but no central component (9+0)

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Retinoblastoma: report ofa case with minimal retinal involvement but massive anterior segment spread

Fig. 6 Vertical section ofthe enucleated eyeshowstumourous infiltration ofthe iris and ciliary body,particularly inferiorly, but the retina shows no abnormalityapartfrom artefactual detachment. Tumour cells are seen inthe posterior chamber and anterior vitreous. Haematoxylinand eosin.

(Fig. 9) and numerous intercellular junctions ofintermediate type.

Discussion

The morphology of the cells at the initial biopsy,while consistent with retinoblastoma, was far fromconclusive and warranted the consideration of alter-native diagnosis. Given that the clinical diagnosis ofuveitis made when the patient first presented was notsubstantiated by an appropriate response to anti-inflammatory drug therapy or the histological

character of the cellular infiltrate, the principalalternative was acute lymphocytic or monocyticleukaemia. This would have needed to be in analeukaemic phase, since examination of theperipheral blood revealed no abnormality, butthe absence of other symptoms and signs madeleukaemic infiltration an unlikely diagnosis. More-over, there was no evidence of cell bound immuno-globulin as might have been expected in the case oflymphocytic neoplasia. Nevertheless, the diagnosisof retinoblastoma was to some extent one of exclu-sion, and the finding of an apparently normal retinawhen the enucleated eye was opened in the labora-tory provoked temporary misgivings, at least, on thepart of the pathologist responsible for the biopsyevaluation. The subsequent demonstration of cilia-like structures with the 9+0 configuration character-istic of retinal photoreceptor cells and of manyretinoblastomas67 served, however, to support thediagnosis, and the finding of intermediate junctionsbetween the cells, while not conclusive evidence ofretinoblastoma, excluded a leukaemic process.The demonstration of neuron-specific enolase in

some cells was also indicative of a neuronal tumour.In a study by Terenghi et al.8 all but one of 30retinoblastomas stained for neuron-specific enolase,irrespective of the degree of differentiation, butother reports910 suggest that this enzyme is usuallyconfined to the more primitive tumours such aspertained in the present case. The demonstration ofS-100 protein is a less reliable marker of retino-blastoma, for, while Terenghi et al.8 found it to bepresent in all but five of the cases they examined,others have provided uniformly negative reports.9Immunohistochemical staining for glial fibrillary

acidic protein was negative in the present case, and,

Fig. 7 Theperipheral retina in thesuperior hemisphere shows a littlefocal increase in thickness due to theproliferation ofretinoblastomacells. Haematoxylin and eosin.

- 8..

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Fig. 8 A secondsmallfocus oftumour is seen at the inferior retinalperiphery. Haematoxylin andeosin.

although a positive response has been described inrespect of retinoblastoma cells maintained in tissueculture, "0' others are agreed that the glial elementsdemonstrable in some tumours are not an integralpart of the neoplastic process.8"2 Of the recognised

growth patterns of retinoblastoma the case underconsideration compares most closely with the diffuseinfiltrating type.34I 13 Even so, two isolated focimeasuring 1.5 mm at most, are only partially des-cribed by this designation, and the present case must

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Fig. 9 Transmission electron micrograph ofa tumour celliromtile posterior ctambershowing a 9+O cilia-like structure.Uranyl acetatellead citrate, x200 000.

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Retinoblastoma: report ofa case with minimal retinal involvement but massive anteriorsegmentspread

be regarded as an extreme rarity. The closest analogyin the literature appears to be the case presented byReeser to the Verhoeff Society in 19755 and depictedby Zimmerman,2 but examination of the histologicalsection indicates a slightly more extensive intra-retinal lesion than pertains in our case. They are,nevertheless, both likely to represent one end of aspectrum of the extent to which the retina canmanifest the diffuse infiltrating form of retino-blastoma before presenting with predominantlyanterior segment changes. It is noteworthy, althoughthe relevance is obscure, that the age of the patientbeing reported was 7 years at initial presentation,that Reeser's case was 8 years old, and that seven ofthe 10 cases of diffuse infiltrating retinoblastomadescribed by Morgan3 ranged between 43/4 and 10years in age. Morgan3 commented that retino-blastomas of the diffuse infiltrating type have a betterprognosis than other types, but any prediction in thepresent case is clouded by recurrence of the tumourin the orbit eight months after enucleation.

We are grateful to Mr J D Griffiths, FRCS, who was responsible forthe initial referral and for the enucleation, for permission to reportthis case, and to Dr A C E McCartney for electron microscopicaldata.

References

1 Stafford WR, Yanoff M, Parnell BL. Retinoblastoma misdiag-nosed as primary ocular inflammations. Arch Ophthalmol 1969;82: 771-3.

2 Zimmerman LE. Retinoblastoma and retinocytoma. In: SpencerW, ed. Ophthalmic pathology: an atlas and textbook. 3rd ed.Philadelphia: Saunders, 1985: 1292-351.

3 Morgan G. Diffuse infiltrating retinoblastoma. BrJ Ophthalmol1971;55:600-6.

4 Nicholson DH, Norton EW. Diffuse infiltrating retinoblastoma.Trans Am Ophthalmol Soc 1980; 78: 265-89.

5 Reeser F. Iris spread from a peripheral retinoblastoma.Presented at the Verhoeff Society Meeting, Washington, DC,1975.

6 Popoff N, Ellsworth RM. The fine structure of retinoblastoma:in vivo and in vitro observations. Lab Invest 1971; 25: 389-402.

7 Albert DM, Lahav M, Lesser R, Craft J. Recent observationsregarding retinoblastoma 1. Ultrastructure, tissue culturegrowth, incidence, and animal models. Trans Ophthalmol SocUK 1974; 94: 909-28.

8 Terenghi G, Polak JM, Ballesta J, etal. Immunocytochemistry ofneuronal and glial markers in retinoblastoma. Virchows Arch(A) 1984; 404: 61-73.

9 Molnar ML, Stefansson K, Marton LS, Tripathi RS, MolnarGK. Immunohistochemistry of retinoblastomas in humans. Am JOphthalmol 1984; 97: 301-7.

10 Kyritsis AP, Tsokos M, Triche TJ, Chader GJ. Retinoblastoma:origin from a primitive neuroectodermal cell. Nature 1984; 307:471-3.

11 Jiang Q, Lim R, Blodi FC. Dual properties of cultured retino-blastoma cells: immunohistochemical characterisation ofneuronal and glial markers. Exp Eye Res 1984; 39: 207-15.

12 Lane JC, Klintworth GK. A study of astrocytes in retino-blastomas using the immunoperoxidase technique and anti-bodies to glial fibrillary acidic protein. Am J Ophthalmol 1983;95:197-207.

13 Schofield PB. Diffuse infiltrating retinoblastoma. Br JOphthalmol 1960; 44: 35-41.

Acceptedfor publication 31 October1986.

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