Complications of management in primary acquired melanosis with atypia

The management of conjunctival primary acquired melanosis (PAM) with atypia is in flux. Lesions are treated with biopsy, excision, adjunctive cryotherapy, or topical mitomycin.¹ Acceptable, usually minimal, complications have been reported with these adjunctive therapies.² Adverse events associated with topical mitomycin are uncommon and punctual stenosis is observed, especially in cold windy climates in approximately 20% of cases. Limbal stem cell deficiency has been described after the use of this agent on a dose‐related basis, but is uncommon.²,³

We report a case of recurrent PAM with atypia treated with three courses of mitomycin and two courses of cryotherapy, with subsequent stem cell deficiency and vision loss that was reversed with an autologous stem cell transplant. We received human experimentation committee (CCPMC Human Experimentation Committee) approval for this study.

Case report

A 56‐year‐old woman presented with an enlarging area of right conjunctival and corneal pigmentation. It started to expand five years ago with marked growth over the past six months. She had 20/30 visual acuity in the involved right eye; the left eye was unremarkable. There was circumferential superficial right limbal pigmentation with a thickened area inferiorly to the inferior fornix, as well as pigment dusting the caruncle. We resected the inferior corneal‐conjunctival area of thickened pigmentation, which showed PAM with atypia. The surgical margins were clear. Adjunctive double freeze–thaw cryotherapy was used. She received two one‐week courses of postoperative mitomycin C, 0.04% three times a day. There was some regression of the remaining pigmentation over the next few months. Approximately six months later, there was an area of increased limbal pigmentation, which we treated with an additional one‐week course of mitomycin. This produced marked diminution of pigmentation.

Five months later she developed increased pigmentation, which was treated with a one‐week course of 0.4% mitomycin with a marked decrease of the pigmentation.

Pigmentation remained superficial and stabilized for approximately a year, and then she developed an additional spread of flat pigmentation without new vessels or increased thickness. We treated this area of involvement in the superior conjunctiva with double freeze–thaw cryotherapy, with marked diminution of pigmentation.

Two and a half years from our initial intervention, she developed new areas of pigmentation that were flat, and these were treated with another two‐week course of topical mitomycin. This produced a marked clearing of the pigment.

Five months later, she developed decreased vision in the right eye with corneal epithelial irregularity. This progressed, and on examination four months later the visual acuity was 20/200, with epithelial edema. We used an autologous limbal stem‐cell transplant from the opposite eye, with return of vision to 20/20. There was no residual pigmentation noted.

Comment

There are few reports of severe toxicity with either mitomycin or cryotherapy in the management of superficial conjunctival neoplasms.¹ Limbal stem‐cell deficiency has previously been reported by us and others.⁴ It is likely as some patients are managed with recurrent disease by repeated applications of these therapies, especially a combination of mitomycin and cryotherapy, that they are more likely to produce stem‐cell deficiency. In this report we have shown again that stem‐cell transplantation is useful in repairing visual loss in this setting.