A rare presentation of pigmented paravenous retinochoroidal atrophy.

A 21-year-old female patient presented with gradual progressive loss of vision in both eyes of 12 years duration. Funduscopic examination revealed bone-spicule pigmentation and choroidal and retinal pigment epithelium atrophy along the vascular arcades, with macular involvement in both eyes. The patient was diagnosed with pigmented paravenous retinochoroidal atrophy which is rare disease, uncommon in females, more commonly affecting the paravascular fundus. Very few cases of macular involvement have been reported.

Introduction

Pigmented paravenous retinochoroidal atrophy (PPRCA) is a rare disease, of unknown origin, characterized by retinochoroidal atrophy and retinal pigmentation along retinal veins, generally without macular involvement.[1]

Case Report

A 21-year-old Asian female presented with painless, progressive diminution of vision of insidious onset in both eyes of 12 years duration. There was no history of trauma or prior inflammatory episodes. Family history was unremarkable. Her best corrected visual acuity (BCVA) was 6/60, N36 in the right eye and 3/60, N36 in the left eye. The anterior segment was unremarkable in both eyes. Examination of the fundus revealed areas of pigmented chorioretinal atrophy extending along the retinal vessels and affecting the macula and the peripheral fundus alike. Multiple areas of bony spicule pigmentation were noted along the veins. Posterior pole showed extensive scarring. A beaten-metal appearance was noted at the macula with scarring at the fovea [Figure 1a and b]. Fundus autofluorescence images revealed hypo-autofluorescent areas corresponding to the atrophic patches over the posterior pole [Figure 1c and d]. Electroretinogram (ERG) showed normal scotopic responses with reduced photopic responses in both eyes [Figure 2]. A diagnosis of PPRCA was arrived at. The nature of the disease was explained and low vision aids were prescribed.

Figure 1

(a, b) Color fundus photographs (montages) of the right and left eyes showing extensive chorioretinal atrophy along the vessels along with macular scarring. (c, d) Autofluorescence images of the right and left eyes showing total loss of autofluorescence from the areas of chorioretinal atrophy

Figure 2

Full-field electroretinogram of both eyes showing normal scotopic and reduced photopic responses

Discussion

PPRCA is a rare disease, so described by Franceschetti because of the diagnostic clinical appearance.[1] This disease commonly is detected on routine examination and majority of patients remain asymptomatic. Males are more commonly affected than females and it is commonly bilateral.[1] A review of literature reveals that very few cases of PPRCA have been described in females and involvement of macula is even more rare. In the present case the visual acuity at presentation was poor caused by the macular involvement. There was no evidence of ocular inflammation. Although earlier reports have suggested a possible post-inflammatory etiology such as tuberculosis, rubeola and syphilis as possible causes, a definite etiology remains elusive.[2] Typically, bone corpuscle pigmentation is seen along the distribution of the retinal veins. Areas of chorioretinal atrophy are seen along the vessels including the peripapillary area. This disease usually spares the rest of the retina, arterioles and the macula. Very few cases of macular involvement have been described.[2]

Electrodiagnostic tests results reported in the literature vary from normal to extinguished ERG.[123] Our patient showed normal scotopic responses with reduced photopic responses secondary to macular involvement.

No established mode of inheritance has been described with various reports suggesting dominant, recessive X-linked and Y-linked modes of transmission.[4] Most cases described have been sporadic and may represent an acquired response pattern to an infectious or inflammatory disease. Both stationary and progressive course of this disease have been described.[135] Although mutation in the CRB1 gene has been reported to be associated with PPRCA, our patient did not have genetic testing done even though it was advised.

In conclusion, PPRCA can uncommonly present in young adult females with insidious onset and gradual progression even involving the macula.