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Persistent hyperplastic primary vitreous


Key points

  • Definition: Pathologic entity caused by abnormal hypertrophy of the ocular hyaloid system.

  • Classic clue: Child presenting at or soon after birth with leukocoria, micropthalmia, fluid-fluid level, no calcifications, and persistent Cloquet’s canal is virtually pathognomonic.

  • In normal embryologic development, the primary vitreous is replaced by the adult secondary vitreous and does not normally hypertrophy or persist to infancy or childhood.

  • Persistent hyperplastic primary vitreous (PHPV) is the second most common cause of leukocoria after retinoblastoma and is a very important differential. ,

  • Microphthalmia.

  • Commonly causes immature cataract with lens opacity on computed tomography (CT).

  • More than 90% are unilateral.

  • Marked vitreal hyperintensity on T1, proton density, and T2 with conspicuous fluid-fluid level.

Imaging

Computed tomography features

  • Microphthalmia.

  • No calcifications (as in retinoblastoma). ,

  • Increased vitreous attenuation. ,

  • Enhancement of abnormal intravitreal tissue (if contrast given).

  • Fluid-fluid levels from breakdown of recurrent hemorrhage.

  • Lens may be small and irregular.

  • Often shallow anterior chamber (type I anterior PHPV).

  • Optic nerve (ON) may be small. Computed Tomography

Recommendations

  • Less preferred, but may be first imaging study.

    • Radiation to orbit undesirable.

    • No calcifications (as in retinoblastoma). Magnetic Resonance Imaging Features

Magnetic Resonance Imaging Features

  • Characteristic hyperintense T2 signal differentiates this from retinoblastoma, which has hypointense T2 signal.

  • Microphthalmia.

  • Fluid-fluid level.

  • Hypointense to isointense thin triangular band extending from optic disc to lens.

  • Marked hyperintensity of vitreous on T1, proton density, and T2.

    • Related to proteinaceous fluid/methemoglobin (from hemorrhagic blood degradation products).

  • Avid enhancement of fibrovascular intravitreal mass.

  • Retinal detachments frequent:

    • Type A detachment from ON.

    • Type B detachment from point on wall eccentric to ON.

  • Exact findings depend on type:

    • Anterior, posterior, or combined.

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