The role of mast cells in vascularized recurrent pterygium.

Objective: To determine and compare the mast cell count in primary and recurrent vascularized pterygium, and in normal bulbar conjunctiva. Methods: The study included 22 patients with primary pterygium (PP group) and 28 patients with vascularized recurrent pterygium (VRP group) that underwent excision via the limbal conjunctival autograft technique. Normal conjunctiva samples were collected from the superotemporal bulbar conjunctival region, just temporal to the site from which the autograft conjunctival tissue was harvested. The total number of mast cells in the pterygium (primary and recurrent) and control tissue samples was calculated microscopically using 1% toluidine blue stain under 400× magnification. Results: The mean mast cell count in primary and vascularized recurrent pterygium tissue was 7.45 ± 2.06 mm-2 and 16.11 ± 4.33 mm-2, respectively, and the difference was significant (independent samples t-test, P<0.001). The mean mast cell count in pterygium tissue was significantly higher than that in normal conjunctiva tissue in both groups (Student's t-test, P<0.001). Conclusion: An increase in the number of mast cells might play a role in the pathogenesis of recurrent pterygium. Determination of a mast cell count cut-off value could be of diagnostic significance for recurrent pterygium.