Electron microscopic features of nasal mucosa treated with topical and circumostial injection of mitomycin C: implications in dacryocystorhinostomy.

Abstract

To evaluate the ultrastructural effects of topical and circumostial injection of mitomycin C (COS-MMC) on nasal mucosa and compare them with the controls. The study also aimed at classifying the subcellular effects in detail. The nasal mucosa of 6 patients were subjected to 0.02% of mitomycin C for 3 minutes (3 patients) and 0.02% COS-MMC (3 patients) as per standard protocol, during endoscopic dacryocystorhinostomy. Normal nasal mucosa from untreated areas (2 each from topical and COS-MMC groups) were taken as controls after harvesting the treated areas. Full thickness tissues (5 mm × 5 mm) were collected for transmission electron microscopy, and ultrastructural effects were evaluated. Both topical and COS-MMC showed significant and distinct ultrastructural changes involving the epithelial, glandular, vascular, and fibrocollagenous tissues compared with the controls. There were profound changes within fibroblasts with intracellular edema, pleomorphic and vesicular mitochondria, dilated smooth and rough endoplasmic reticulum, and chromatin condensation. In addition, COS-MMC samples showed subepithelial hypocellularity with limited disorganization of structure. The changes in both the MMC groups were restricted to treated areas only. Both topical and COS-MMC show profound changes in nasal mucosa with more marked changes in COS-MMC group. These changes being limited in nature may help in enhancing the success of dacryocystorhinostomy by preventing cicatricial changes of the ostium, especially in high-risk cases such as revision and post-traumatic dacryocystorhinostomy.