a 22 weeks pregnant woman came to us for advice regarding the chance of offspring getting retinoblastoma as her first child had bilateral retinoblastoma .
the other offspring was 1 year and 9 months old at the time of presentation with a history of leukocoria in the left eye .
she was diagnosed to have bilateral retinoblastoma ; group b in the right eye and group d in the left eye ( international classification of retinoblastoma classification ) .
systemic chemotherapy ( four cycles ) and external - beam radiation therapy failed to control the tumor in the left eye and hence the left eye underwent enucleation with ball implant , 8 months after presentation .
the right eye was salvaged with good tumor control and the preservation of vision [ fig . 1 ] .
clinical findings in the sibling showing bilateral retinoblastoma ( a ) ultrasound b scan of the left eye showing large tumor in visit 1 ( b ) fundus drawing of the left eye showing tumor coded by yellow color ( c ) ultrasound b scan of the right eye showing tumor .
( d ) post treatment regressed tumor in the right eye at last follow up ( 7 years follow - up ) a cytogenetic analysis done at that time revealed male karyotype with 13q14 deletion in the father , and the mother was normal .
while the mother was found to be normal , the father revealed a retinoma in his right eye . as direct screening by mutational analysis
is time - consuming and needs more sample , prenatal cord blood was taken for molecular linkage analysis for retinoblastoma .
the fetus was found to have the defective rb1 allele inherited from the father [ fig . 2 ] and
gene tracking ( predictive testing ) in the case of familial retinoblastoma the child was born at 34 weeks and the first ophthalmic evaluation done on the 2 day of life was normal .
the child underwent periodic monthly examination under anesthesia until 2 years of age . at 28 months of age
, she developed a tumor ( group a ) in the inferonasal retinal periphery of the right eye that was treated with cryotherapy [ fig .
the child continued to be under bi - monthly clinical follow - up . visual assessment with lea symbol charts showed the visual acuity of 20/20 in both eyes . at a recent follow - up at 7 years of age , the fundus was stable , and visual acuity maintained in both the eyes .
fundus photographs ( retcam ) of the child with defective allele detected on prenatal diagnosis ( a ) fundus photograph of the right eye at 2 days of birth .
( c ) fundus photograph of the right eye at 28 months showing tumor at inferonasal periphery ( d ) post treatment cryo , regressed tumor at 3 months follow - up
prenatal diagnosis of retinoblastoma with clinical follow - up has been reported earlier , however , to the best of our knowledge , this is the first report from india to show the clinical correlate of genetic findings on a prenatal diagnosis .
it is important for an ophthalmologist to determine the etiology of an unilateral case ( whether it is hereditary or not ) as the management of the patient ( examination of fellow eye , frequency of follow - up and sometimes treatment which should be provided along with genetic counseling ) may be different when compared to a bilateral case .
in this case , already having a child with retinoblastoma ( with one eye enucleated ) prompted the mother to undergo a prenatal screening for the next offspring .
even though primary prevention was not possible in this situation , prenatal diagnosis with serial ultrasound scans of the fetus could help look for a tumor in the fetal eye at an early stage .
if detected in utero , a fetus with retinoblastoma can be delivered early to initiate early treatment and possibly reduce the morbidity and preserve the vision . though the child was identified to have the inherited paternal risk allele
hence , it is likely that these children may develop tumor at a later stage of life alarming for careful and regular long - term surveillance .
thus , prenatal diagnosis offers early detection of the tumors in the course of the disease and periodic examinations aid in eye salvage .
 retinoblastoma is the most common malignant intraocular tumor in pediatric age group if undetected leads to ocular mortality . 
 prenatal diagnosis is an emerging technology to detect fatal diseases in utero such that subsequent management is planned to reduce the ocular morbidity . 
 we describe a case demonstrating the importance of prenatal diagnosis in a child with a strong family history of retinoblastoma and importance of a long - term clinical follow - up in these cases . 
Case Report
Discussion
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