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Abstract #13042 Published in IGR 7-3
Bimatoprost-induced periocular skin hyperpigmentation: histopathological study
Kapur R; Osmanovic S; Toyran S; Edward DPArchives of Ophthalmology 2005; 123: 1541-156
OBJECTIVE: To investigate light microscopic and ultrastructural changes in bimatoprost-induced skin hyperpigmentation. METHODS: Eyelid biopsy specimens from bimatoprost-treated patients and matched controls were examined by light microscopy and transmission electron microscopy. Using an image analyzer, melanin granules were counted on Fontana-Masson-stained sections, and melanosomes were counted on electron micrographs. Immunohistochemical analysis was performed with antibodies against S100 and CD3. Positively labeled cells were counted. RESULTS: By light microscopy, a marked increase in the number of melanin granules was noted in the bimatoprost-treated specimens. Electron microscopy demonstrated dermal melanocytes with prominent rough endoplasmic reticulum and abundant normal-sized melanosomes in different stages of maturation as compared with control specimens. Furthermore, the keratinocytes of the bimatoprost-treated specimens showed abundant mature melanosomes when compared with controls. Also of note, atypical melanocytes were absent in both specimens. The S100-positive melanocytes were comparable in bimatoprost-treated and control specimens. Few CD3- and CD68-positive cells in the bimatoprost-treated specimens were noted in both groups. CONCLUSION: Bimatoprost-induced periocular hyperpigmentation is caused by increased melanogenesis. There was no evidence of melanocyte proliferation or prostaglandin-induced inflammation in the specimens that were examined.
Dr. R. Kapur, Department of Ophthalmology and Visual Sciences, University of Illinois, Chicago 60612, USA
Classification:
11.4 Prostaglandins (Part of: 11 Medical treatment)
