birth history of the child was unremarkable . on initial examination , the size of the cornea looked smaller . the child was referred for ocular ultrasound examination , with a clinical suspicion of retinoblastoma . an ultrasound study was performed with a high - frequency transducer operating at 10 mhz ( l5 , ge medical systems , usa ) . gray scale evaluation revealed an echogenic band in the posterior segment of both globes extending from the posterior surface of the lens capsule to the optic disc . the axial length of the globes was 16 mm , which was suggestive of micro - ophthalmia . hyperechoic foci were seen in both the posterior segments adjacent to the artery , suggestive of associated vitreous hemorrhage [ fig . no calcification was seen . a 3-month - old infant who presented with bilateral leukokoria . ( a ) axial ultrasound image with color doppler shows a vessel running through the vitreous of both globes , from the posterior surface of the lens capsule to the optic disc ( arrowhead ) . ( b ) on pulsed doppler examination , the vessel shows arterial flow computed tomography ( ct ) of the orbits ( lightspeed , ge medical systems , usa ) revealed diffusely hyperdense vitreous in both globes , suggestive of hemorrhage [ fig . 2 ] . subtle linear densities were seen in the vitreous of both globes , representing hyaloid artery in cloquet 's canal [ fig . 2 ] . a 3-month - old infant who presented with bilateral leukokoria . axial ct image shows diffusely hyperdense attenuation of vitreous in both globes , suggesting hemorrhage . subtle linear structures are also seen ( arrowheads ) , representing hyaloid artery in cloquet 's canal based on the above findings , the patient was diagnosed with bilateral phpv . further investigation failed to reveal any history of similar disorder in the family of the patient . the parents were advised to get him examined under general anesthesia , so that appropriate management could be decided . however , the parents were unwilling for a procedure under anesthesia and refused for the examination . the primary vitreous is formed during the first month of development and contains branches of the hyaloid artery . this hyaloid artery begins to regress during the formation of the avascular secondary vitreous at 9 weeks . by the third month , the secondary vitreous , which ultimately forms the adult vitreous , fills most of the developing vitreous cavity . the primary vitreous becomes condensed into a narrow band ( cloquet 's canal ) , running from the optic disc to the posterior aspect of the lens . phpv is classified into three types : anterior , posterior , or a combination of the two . bilateral leukokoria in a child may be due to a number of causes , of which retinoblastoma , congenital cataract , retinopathy of prematurity ( rop ) , severe intermediate uveitis , and retinal dysplasias are the most frequent . bilateral phpv is rare . while analyzing patients presenting with phpv , pollard found two of 83 ( 2.4% ) cases to be bilateral , while haddad et al . found seven of 62 ( 11% ) cases to be bilateral . persistent hyperplastic primary vitreous has a typical imaging appearance , which allows reliable differentiation from retinoblastoma . in phpv , gray - scale ultrasonography shows an echogenic band extending from the posterior surface of the lens capsule to the optic disc . doppler may show arterial flow within this band representing a persistent hyaloid artery [ fig . 1 ] . ct findings of phpv are absence of calcification , increased density of the entire vitreous , tubular intravitreal density ( cloquet 's canal or nonattached retina ) [ fig . 2 ] , decubitus positioning showing a gravitational effect on fluid - fluid level , micro - ophthalmia , enhancement of abnormal intravitreal tissue , and small or irregular lens . magnetic resonance imaging ( mri ) findings of phpv consist of a tubular structure , representing the hyaloid vessel ; a funnel - shaped retinal detachment , with the subretinal fluid hyperintense on both t1- and t2-weighted images ; fluid - fluid level due to the presence of hemorrhage in the subretinal space ; a retrolental mass ; micro - ophthalmia , and vitreous hemorrhage . phpv can be differentiated from retinoblastoma by the absence of a calcified mass , artery running through cloquet 's canal , and typical signal characteristics of retinoblastoma on mri , i.e. , hyperintense on t1-weighted images and hypointense on t2-weighted images . a patent hyaloid artery , as noted in this case , is not a feature of vitreoretinal dysplasias . differentiation from advanced retinopathy of prematurity ( rop ) can be difficult on imaging alone . history of a premature , low birth weight infant undergoing prolonged supplemental oxygen therapy helps to distinguish it from bilateral phpv . complications of phpv include rupture of the lens capsule , cataract formation , intraocular hemorrhage , secondary glaucoma , tractional retinal folds , and subsequent phthisis bulbi . the friability of the hyaloid vasculature predisposes to vitreous hemorrhage , which was noted in both globes in the present case . this entity , although rare , should be considered in the differential diagnosis of retinoblastoma while evaluating bilateral leukokoria .
a case of bilateral persistent hyperplastic primary vitreous ( phpv ) in a 3-month - old male infant , who had bilateral leukokoria , is presented . 
 the child was referred for imaging with a clinical suspicion of retinoblastoma . 
 gray - scale ultrasound evaluation revealed an echogenic band in the posterior segment of both globes , extending from the posterior surface of the lens capsule to the optic disc . 
 doppler examination revealed the presence of arterial flow in the band in both globes . 
 associated echogenic hemorrhage was also seen , which was confirmed by computed tomography . 
 most cases of phpv are sporadic and unilateral , and bilateral phpv is rare . 
 the imaging features in this case suggest the diagnosis of bilateral phpv and differentiate it from retinoblastoma . 
 this entity , although infrequent , should be considered in the differential diagnosis while evaluating bilateral leukokoria .