Indian Journal of Ophthalmology

CASE REPORT
Year
: 1995  |  Volume : 43  |  Issue : 1  |  Page : 27--29

Trilateral retinoblastoma: CT evaluation


Srikrishna V.V Nunna, Raju Sharma, Sushma Vashisht, Manorama Berry 
 From Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
Sushma Vashisht
Department of Radiodiagnosis, All India Institute of Medical Sciences, New Delhi 110 029
India




How to cite this article:
Nunna SV, Sharma R, Vashisht S, Berry M. Trilateral retinoblastoma: CT evaluation.Indian J Ophthalmol 1995;43:27-29


How to cite this URL:
Nunna SV, Sharma R, Vashisht S, Berry M. Trilateral retinoblastoma: CT evaluation. Indian J Ophthalmol [serial online] 1995 [cited 2020 Apr 2 ];43:27-29
Available from: http://www.ijo.in/text.asp?1995/43/1/27/25273


Full Text

Trilateral retinoblastoma (TRB), a syndrome described in 1980 by Bader et al,[1] is characterised by bilateral ocular retinoblastoma and the. presence of a similar primary intracranial midline neuroblastic neoplasm. To date, 19 cases have been reported in the English literature.[2][3][4][5][6][7] Herein, we present the computed tomography (CT) evaluation of a patient of TRB with incidental bilateral basal ganglia and temporal lobe calcification.

 CASE REPORT



A one-year-old boy presented with a history of a white reflex in both eyes, noticed in the left eye at ten months of age and two months later in the right eye. The child was delivered normally and there was no history of birth trauma, asphyxia, or congenital infection. There was no previous maternal abortions or retinoblastoma in the family.

Ophthalmoscopy under anaesthesia revealed an irregular tumour in the inferonasal quadrant of the fundus of the right eye. The optic disc was normal. The left eye was phthisical with a cataractous lens.

A-mode ultrasonography confirmed the ophthalmoscopic observations in the right eye. The left eye had cataractous lens, and an irregular soft tissue mass with calcification, vitreous debris and retinal detachment. Based on the above findings, a diagnosis of bilateral retinoblastoma with vitreous debris, retinal detachment and phthisis bulbi in the left eye was made.

Radiotherapy of 50 cGy was given to both orbits over a period of 5 to 6 weeks. The patient was followed up by regular ophthalmoscopic and ultrasound evaluations for 6 months. A reduction in the size of the tumour was noticed during the follow-up. In order to evaluate the extent of lesions, a CT scan was carried out.

Axial noncontrast computed tomography (NCCT) and contrast-enhanced computed tomography (CECT) of the orbits and head was performed. NCCT of orbits revealed a soft tissue mass of increased attenuation with calcification located in the inferomedial quadrant of posterior segment of the right eye [Figure:1]. The left eye showed an irregular soft tissue mass of increased attenuation with large nodular calcification occupying most of the posterior segment. The left globe was smaller in size compared to the right. The optic nerves, extraocular muscles, retrobulbar fat and bony orbit on both sides were normal [Figure:1]. CT of the head revealed an isodense, crescent-shaped soft tissue mass posterior to the third ventricle in the region of the pineal gland. There were faint specks of calcification in the mass [Figure:2]A, [Figure:2]B. It showed homogeneous enhancement on contrast administration [Figure:3]. The basal ganglia and anterior parts of temporal lobes on both sides showed punctate calcification on NCCT [Figure:1], [Figure:2]A. The rest of the brain parenchyma was normal. These findings were suggestive of bilateral retinoblastoma with pineal tumour (TRB), left phthisis bulbi and bilateral basal ganglia and temporal lobe calcification.

The parents were advised about the need for surgery of the pineal tumour. As the child was asymptomatic, the parents refused surgery.

 DISCUSSION



Retinoblastoma is considered to be genetically transmitted.[2],[3],[7] Eighteen percent of bilateral cases are familial and sixty percent of familial cases are bilateral.[7] A higher familial incidence is seen in patients with TRB.[2],[7] No evidence of positive family history was available in our patient.

Since all the patients in the reported cases had bilateral intraocular tumours,[2][3][4][5],[7] presumably they had the retinoblastoma gene that rendered all of their retinal cells susceptible to neoplastic transformation. Bader et al[2] suggested that retinoblastoma occurs in the photoreceptor tissue of both eyes and in the vestigeal photoreceptor tissue in the pineal gland, which they referred to as "ectopic retinoblastoma." These tumours were different from a variety of other cancers, mostly sarcomas that subsequently develop in 10 to 15% of survivors of heritable retinoblastoma.[2],[8],[9]

Retinoblastoma has slight female predilection with male/female ratio of 2:3 and the mean age at diagnosis of retinoblastoma is usually 6 months and that of pineal tumour is 4 years.[2] Our patient was a male child and was diagnosed to have retinoblastoma at the age of 1 year and pineal tumour at 1.5 years. As illustrated in our patient and also reported in the literature,[2],[3],[7] CT scan has proved to be very useful in diagnosing TRB. Nine of the 19 cases reported in the literature had histological proof from surgery, biopsy or autopsy.[2][3][4][5][6][7] The diagnosis and management were based on clinical presentation, ophthalmoscopy, ultrasonography and CT scan findings.

In patients of bilateral retinoblastoma early detection of the presence of a pineal tumour is essential as this is a major cause of mortality. [10] The pineal tumours were diagnosed by CT scan in 12 of the 19 reported cases. In the case under report, pineal tumour was diagnosed incidentally on CT scan before the patient became symptomatic of intracranial pathology. In the earlier reported cases the pineal tumour was diagnosed either after it became symptomatic[2,3,7] or before the detection of ocular tumour itself.[2] The pineal tumour presents as a dense soft tissue mass with or without calcification and variable enhancement on CT. The significance of the presence of additional finding of calcification of basal ganglia and temporal lobes in our patient could not be explained.

Based on the experience, we recommend that a baseline CT scan of the orbits and brain parenchyma should be carried out in all patients of bilateral retinoblastoma in order to rule out any pineal gland tumour[10].

References

1Bader JL, Miller RW, Meadows AT, et al. Trilateral retinoblastoma. Lancet 2:582-583, 1980.
2Bader JL, Meadows AT, Zimmerman LE, et al. Bilateral retinoblastoma with ectopic intracranial retinoblastoma: Trilateral retinoblastoma. Cancer Genet Cytogenet 5:203-213, 1982.
3Brownstein S, de chadarevian JP, Little JM. Trilateral retinoblastoma. Report of two cases. Arch Ophthalmol 102:257-262, 1984.
4Donoso LA, Felberg NT, Shields JA, et al. Antigens in primary intracranial tumor with retinoblastoma. Invest Ophthalmol Vis Sci (ARVO Abstracts) Suppl 2:33, 1980.
5Jakobiec FA, Tso Mo, Zimmerman LE, et al. Retinoblastoma and intracranial malignancy. Cancer 39:2048-2058, 1977.
6Jensen RD, Miller RW. Retinoblastoma: Epidemiological characteristics. N Engl J Med 285:307-311, 1971.
7Johnson DL, Chandra R, Fisher WS, et al. Trilateral retinoblastoma: Ocular and pineal retinoblastoma. J Neurosurg 63:367-370, 1985.
8Abramson DH, Ellsworth RM, Zimmerman LE. Nonocular cancer in retinoblastoma survivors. Trans Am Acad Ophthalmol Otolaryngol 81:454-457, 1976.
9Abramson DH, Ronner HJ, Ellsworth RM. Second tumors in nonirradiated bilateral retinoblastoma. Am J Ophthalmol 87:624-627, 1979.
10Zimmerman LE. Trilateral retinoblastoma. Ophthalmology Suppl 89:86, 1982.