Department Obstetrics Gynecology, Rambam Medical Center, Haifa, 31096 Israel.

Introduction

The temporary vascular networks of the eye provides nutrition during the rapid growth of embryonic development. These vessels regress in the third trimester as a part of the adaptation process of the light transmission through the lens to the retina. Persistent hyperplastic primary vitreous is a developmental malformation of the eye due to the presence of hyperplastic retrolental fibrovascular membrane with persistence of the posterior portion of the tunica vasculosa lentis and hyaloid artery. This abnormality is usually unilateral and associated with microphthalmia, cataract, and glaucoma.

Synonyms: persistent tunica vasculosa lentis, persistent posterior fetal fibrovascular sheath of the lens, congenital retinal septum, ablatio falciformis congenita, persistent fetal vasculature or persistent fetal vasculature syndrome.

There is controversy about the classifications of the disease. We prefer the following classification of the disruption of the regressive process of the hyaloid artery:

1) Complete disruption which is usually associated with microphthalmia cataract and blindness (Image 1)
2) Posterior remnant which is usually associated with normal vision - Bergmeister's papillae (Image 2)
3) Anterior remnant has a normal vision - Mittendorf's  Dot (Image 3) 
4) Persistent fetal vasculature and minimal fetal vascular remnants, phenomenon which may result in congenital cataract (Image 4)

Incidence

The incidence is very low and unknown. Cases occur usually sporadic but both dominant and recessive forms of this disorder have been described.  It is responsible for 4.8% of childhood blindness and visual impairment in the United States. [2] The incidence is very low and unknown. 

The eye involvement is usually unilateral. Bilateral Persistent hyperplastic primary vitreous is usually associated with other anomailes such as trisomy 13, 15, 18, Norrie disease and Walker Warburg syndrome. [1,3,4,5]

Prenatal diagnosis

The most of the pediatric pathology textbooks mention that persistent hyaloid artery should not be visualized after 7th month of gestation. Birnholz stated that the visualization of the hyaloid artery after 32 weeks of gestation is always considered an abnormal finding [5]. 

Persistent hyperplastic primary vitreous was first reported prenatally by Katorza et al. [8]. We are afraid that the conclusions in this paper may be misleading and could lead to the wrong diagnosis in the future. We are not convinced that the cases described by Katorza can actually be diagnosed as a Persistent hyperplastic primary vitreous because they lack all the information which are necessary for diagnosis, such as history and  genetic  background, sonographic findings and histopathological findings. 

Postnatal diagnosis 

Postnatal diagnosis is possible by slit lamp fluoroscopy, MRI and ultrasound illustrating the wide fibrovascular structure which runs through the vitreous from the posterior aspect of the lens to the retina.

Images 1,2: Image 1 shows persistent hyaloid artery, cataract and persistent hypertrophic primary vitreous resulting in abnormal vision. This case is caused by a complete failure of regression of the embryological, primary vitreous and hyaloid vasculature. Image 2 shows posterior remnant of the hyaloid artery, so called Bergmeister's papillae, the vision is normal.

Case report

This is a case of a 22-year-old G1 P0 with non-contributive personal and family history. Her first ultrasound scan was done at 22 weeks and reported as normal.

She was referred to our department at 34 weeks of gestation for a suspicion of cytomegalovirus infection with a severe intrauterine growth restriction (34/27 weeks), decreased amount of the amniotic fluid, mild ventriculomegaly and bilateral cataract. Our exam confirmed the referral findings. Our additional findings were absent cerebellar vermis, Tetralogy of Fallot, echogenic kidneys and polydactyly.

Persistent hyperplastic primary vitreous was found bilaterally.

The final diagnosis was trisomy 13.

Images 1,2: Image 1 shows an example of the congenital cataract in 15 weeks. Image 2 shows congenital cataract with persistent hyaloid artery at 34 weeks.