A clinicopathologic outlook on end-stage pars planitis: Insights from histopathologic and immunohistochemical study of an enucleated globe

Pars planitis is a subset of intermediate uveitis defined by the presence of inflammation in the vitreous cavity without systemic involvement. Little is known about the histology and immunohistochemistry of pars planitis, owing to the difficulty in procurement of the eyeball specimen, especially with the advent of newer immunomodulatory therapy. We report the histopathology and detailed immunohistochemical study of an enucleated globe of a case of end-stage pars planitis. An 8-year-old male presented to us with decreased vision in both eyes for 5 years. He was seen by a local ophthalmologist and diagnosed as pars planitis in both eyes. The treatment details were not available. Examination here showed phthisical right eye and band-shaped keratopathy, occlusio pupillae, tractional retinal detachment with diffuse choroidal thickening in the left eye. The right eye became a painful, blind eye and was enucleated. The histopathological study of the globe showed disorganized uveal tissues with acellular fibrous tissues within the iris, pars plana, and ciliary body. Lymphocytic infiltration, calcification, and large areas of eosinophilic acellular tissue were seen. Immunohistochemical analysis showed gliotic membranes stained with glial fibrillary acidic protein, CD3-positive T cells, and few CD20-positive B cells were seen. CD68 cells were noted over epithelioid histiocytes. Epithelioid cells and giant cells showed Human leukocyte antigen - DR (HLA-DR) positivity. Our study provided the pathological and immunohistochemical features in a case of enucleated specimen of pars planitis, indicating a predominantly T-cell-mediated process. Future studies are needed for further understanding of the pathology and for the advent of newer pharmacological therapies.