Purchase this article with an account.
I. Pecorella, E.M. Vingolo, L. Carlomusto, P. Grenga; Scleral Ossification: An Unusual Finding . Invest. Ophthalmol. Vis. Sci. 2006;47(13):5614.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
We report two cases of both scleral and intraocular ossification incidentally detected in patients with long–standing ocular phthisis.
Case 1. A 45–year–old woman with post–traumatic cataract and untreatable glaucoma in the RE, secondary to a knife penetrating injury, which had occurred 35 years earlier. Case 2. A 34–year–old woman with a phthisical RE secondary to uveitis and untreatable retinal detachment of 15–year duration. In both instances, evisceration of the ocular content and insertion of a cosmetic prosthesis was planned. At surgery, a hard mass measuring 1 x 1 cm was palpated in the inferior quadrants of the sclera and excised for histological examination. Physical examination and laboratory exams failed to show any abnormalities. The specimens were fixed in 10% formol saline, decalcified in EDTA and processed for paraffin embedding.
Microscopically, the uveal and retinal tissue appeared to have undergone extensive fibrosis and reactive gliosis and contained small islands of bone encircled by retinal pigment epithelium (RPE) cells. They appeared to origin from calcified areas surrounding small arteries. Mature lamellar bone, containing well–defined medullary cavities with signs of haematopoietic activity, had formed in the sclera and partially extended to the outer layers of the choroid, well as to the orbital border. There was no evidence of cartilage.
Heterotopic secondary ossification of the eye usually affects intraocular tissues and ensues long after traumatic or long–standing events, which eventually lead to phthisis bulbi. Although calcium deposition in the scleral lamellae is not uncommonly observed, bone formation is only rarely associated with chromosomal abnormalities or colobomatous eyes. The most credited origin for intraocular bone is from metaplastic RPE cells, which are assumed to undergo fibroblastic and osteoblastic differentiation after adequate inflammatory or traumatic stimulus. However, the recent observation that retinal vascular pericytes can differentiate into osteoblast–like cells casts a new light on the possible source of osteoprogenitor cells for heterotopic bone formation in the eye. In our cases, small islands of bone in the gliotic tissue appeared to origin from calcified areas surrounding small arteries in the disorganised retinal remnants. The cases of idiopathic scleral ossification, albeit exceedingly rare, suggest that osteogenic precursor cells may reside in the sclera, as well and though very rarely, these cells can also be stimulated to form heterotopic bone by a traumatic or inflammatory local event.
This PDF is available to Subscribers Only