Mast cells and pterygium.

A total of thirty pterygia were studied for mast cells using metachromatic dye (toluidine blue) together with routine histological stains. On microscopic examination, the lesion was differentiated and classified into angiomatous, fibrous and mixed varieties based on the vascular and collagenous components. The mast cell counts were undertaken in all types and were found to have significant correlation with the morphological types when compared to normal conjunctiva. 15.1 +/- 3.1, 22.7 +/- 3.8, 9.5 +/- 3.2 mast cell per mm2 were found in the angiomatous, mixed and fibrous types respectively. In the control material, the mast cell count was 12.4 +/- 2.3 per mm2. The results are discussed. It is believed that mast cells are actively involved in the genesis and progress of pterygium.