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Persistent hyperplastic primary vitreous

Dr Jeremy Jones and Dr Yuranga Weerakkody et al.

Persistent hyperplastic primary vitreous (PHPV), (also known as persistent fetal vasculature) refers to a rare congenital developmental malformation of the eye.

Clinical presentation

Clinically, this condition usually manifests as unilateral or bilateral leucocoria. Patient's may also have poor vision, small eye (microphthalmia) and strabismus.

Pathology

It arises due to a failure of normal regression of the embryonic hyaloid vascular system. In the normal situation the primary vitreous forms around 7 ^th week of gestation life and starts involuting around 20 ^th week and nearly always disappears at the time of birth. Persistent fetal vasculature in PHPV can lead to fibrosis, resulting in elongation of the ciliary processes, retinal detachment, and spontaneous cataracts.

Sub types

PHPV can be divided into either anterior(ventral) or posterior(dorsal) types with most patients with PHPV having a combination of these ³.

Associations

PHPV can occur on its own or association with various other conditions (particularly) when bilateral, these include ⁹

Radiographic features

From an imaging standpoint, only the features of posterior PHPV are well known ³.

General

In posterior PHPV, the globe is small and can contain contains retinal detachments.

Ocular ultrasound

An echogenic band maybe seen in the posterior segment of the globe extending from posterior surface of the lens to the optic nerve head. On colour Doppler, arterial blood flow was may be seen within this band.

CT

The CT appearance can be quite variable ⁹ and the described spectrum of CT findings includes ¹

soft-tissue replacement (infiltration) of the vitreous body
retrolental soft tissue along the Cloquet canal - fine linear structure
extending from the head of the optic nerve to
the posterior surface of the lens ³
absence of abnormal calcification within the orbit
microphthalmus
retrohyaloid layered blood
hypervascularity of the vitreous humor - after contrast administration, the
vitreal abnormalities may enhance, which is believed to reflect a persistent hypervascular vitreous
retinal detachments can be hyperdense on CT

Differential diagnosis

clinically it is one of the more important and frequent conditions that can mimic a retinoblastoma
at ultrasound the main differential is of retinal detachment