Histopathologic analysis of palpebral conjunctiva in thyroid-related orbitopathy (an american ophthalmological society thesis).

PURPOSE: To examine the histopathology of palpebral conjunctiva in patients with thyroid-related orbitopathy. Based on previously published anecdotes, the hypothesis is that conjunctiva shows increased inflammation and fibrosis.
METHODS: This was a comparative case series. Superior palpebral conjunctiva was examined from two groups. The study group consisted of 20 patients undergoing thyroid-related upper eyelid retraction surgery. The control group consisted of 18 patients undergoing ptosis repair. Specimens were processed and stained using hematoxylin and eosin and trichrome. Histopathologic grading was performed using light microscopy. Main outcome measures were degree of inflammation and fibrosis, mast cell infiltration, and fibroblast count.
RESULTS: The two groups did not differ with regard to age or gender. Mean degree of inflammation was 1.4 (95% CI: 0.9, 1.9) for the control group and 1.7 (95% CI: 1.3, 2.1) for the study group. Relative intensity of blue from trichrome staining mean was 134.3 (95% CI: 130.3, 138.3) for the control group and 138.6 (95% CI: 133.7, 143.6) for the study group. The Mann-Whitney test showed no difference between groups in inflammation (P=.17), relative blue intensity (P=.11), degree of mast cell infiltration (P=.61), and fibroblast count (P=.45). Point estimates show a trend toward greater inflammation in the study group.
CONCLUSIONS: While there is a trend toward higher inflammation in the study group, the superior palpebral conjunctiva of patients with thyroid-related orbitopathy is largely spared from autoimmune changes. This has implications in surgical approaches to eyelid retraction repair.