Abstract
Purpose :
Purpose: After topical treatment for atypical junctional conjunctival melanocytic proliferations, clinically apparent conjunctival pigmentation may remain or change in appearance. The histopathology of primary acquired melanosis with atypia (PAM with atypia)/conjunctival melanoma (CM) in patients treated with the topical chemotherapeutic agent mitomycin-C (MMC) with clinically concerning residual conjunctival pigmentation has not been well described. We hypothesized that like some skin melanomas after local or systemic therapy, histopathology of biopsied residual pigmentation may show tumoral melanosis, rather than evidence of a residual atypical melanocytic proliferation.
Methods :
Methods:A retrospective observational study identified and characterized four sets of post-treatment conjunctival map biopsies from the surface of eyes treated with topical Mitomycin C. Review of clinical data, imaging, hematoxylin and eosin (H&E) stained sections and Melan-A immunohistochemical stained sections was undertaken.
Results :
Results: Four sets of biopsies from female patients aged 58-83 years who underwent treatment of background PAM with atypia with MMC after resection of CM were reviewed. All specimens showed no melanocytic proliferation, and in fact, no residual melanocytes, on H&E or Melan-A immunostained sections. Specimens showed evidence of treatment effect in the form of subepithelial fibrosis and melanin pigment incontinence (pigment within histiocytes) in the substantia propria.
Conclusions :
Conclusion: PAM with atypia/CM, when treated with topical MMC, may show residual clinically concerning irregular and dark conjunctival pigmentation. Biopsy with diagnostic histopathology reveals a similar phenomenon to “tumoral melanosis” in treated cutaneous melanoma and metastases, with only pigmented histiocytes in the substantia propria and no viable remaining neoplastic melanocytes.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.