There are many queries that need to be clarified in this controversial subject. Gibson suggested the term “posterior phlyctenular keratitis” for a pearly lesion in the anterior chamber in a woman with previous superficial phlyctenular keratitis. He also described that this lesion was a low-grade allergic inflammatory process deep in the cornea.3
In 1994, Kroosh and Ahmed2
concluded that there was no cyst wall found whatsoever in each of the samples removed from 34 eyes, and also confirmed the presence of lymphocytes, polymorphonuclear leucocytes, pus cells, RBCs with some histocytes, and plasma cells. The examination of the excised specimens revealed the presence of chronic non-granulomatous inflammatory cells, and added that adherence of some iris to the cornea with the presence of fibrin also supported the view towards an inflammatory and immunological nature of this lesion.
In our study, all of the patients presented with the clinical picture of “iridocyclitis,” which included pain, photophobia, reduced vision, and ciliary injection. The signs were associated with severe inflammatory reaction in the anterior chamber (+3 or +4) with aqueous flare, and four patients presented with pupil distortion. The similarity between the clinical picture of such cases and that of iridocyclitis, and the predilection to the lower part of the iris, gave an impression that these lesions are due to an inflammation inside the eye.
There have been many reports7
about iris cysts, both primary and secondary, in children. Primary cysts have shown a more benign course, and secondary ones a more aggressive and inflammatory course. It has also been reported that primary epithelial cysts have a more benign clinical course than primary stromal cysts.7
Secondary iris cysts have been mainly associated with uveitis.7
Moreover, most of the reported iris cyst cases with a pearl-like appearance were secondary cysts.12
As all anterior chamber lesions in this study had pearly appearance and were associated with anterior uveitis, we thought that these lesions could be secondary cysts. To confirm the noncystic pattern for these lesions, we did anterior segment SD-OCT, which allowed us to show that lesions included in our study were solid in nature and not cystic, and we were able to exclude this possibility in all included patients.
Accordingly, it is highly unlikely that these lesions are iris or implantation cysts, and the favorable response to steroids, especially subconjunctival injection of combined short- and long-acting betamethasone, points to the probability that this pearl-like lesion is an immunological reaction to an unknown antigen, especially given that most of our patients were old enough to exclude the congenital nature of these lesions.
Entamaeba histolytica, Hymenolepis nana
and Enterobius vermicularis
were among the implicated organisms causing phlyctenulosis.16
The former two of these parasites were found in the stool analyses of two children who had pearl-like lesions in our study, and these patients were malnourished and underweight.
Some similarities may exist between these lesions and phlyctenulosis. Both conditions occur in children living in poor socioeconomic standards; are recurrent; present as grayish-white circumscribed lesions in the vicinity of the limbus; and respond to steroid treatment. According to these findings, we think that malnourishment and parasitic infestation may have a role in the occurrence of these pearl-like lesions.
SD-OCT imaging of the anterior segment allowed us to exclude the cystic nature of this lesion and to solve in great part this mysterious finding. Also, the SD-OCT gave an interpretation for the pear-shaped pupil appearance that was associated with these lesions by showing the contact between these lesions and the front surface of the iris both before and after treatment ( and ).
This pearly lesion in the anterior chamber could be a posterior form of phlyctenular keratitis, and future studies are needed to confirm the correlation between well-known superficial phlyctenular keratitis and these anterior chamber pearl-like lesions ().