Abstract
Purpose::
To review personal experience with primary acquired melanosis of the conjunctiva (PAM) and compare findings with prior reports from the Armed Forces Institute of Pathology (AFIP), that recommended biopsy in all cases.
Methods::
Chart review of patients with PAM to determine demographic features, clinical characteristics, clinical course, progression to melanoma, and outcome according to degree of cellular atypia, and treatment complications, The data were analyzed statistically with regard to factors predictive of enlargement, and evolution into melanoma.
Results::
Literature review suggested that PAM may be present in >30% of adult Caucasians. In our series, there were 311 affected eyes in 276 patients. The mean patient age at diagnosis was 56 years (range 15-90 years), 62% were female, and 96% Caucasian, There was a predilection for temporal quadrant (57%). Initial management was observation in 198 (64%), biopsy combined with cryotherapy in 107 (34%), topical chemotherapy alone in 2%. Among those that underwent biopsy and had no atypia, none progressed to melanoma. Of those with atypia, 13% progressed to melanoma. If atypia were mild, 2% progressed to melanoma and if the atypia were severe, 32% progressed to melanoma. Kaplan Meier estimates showed that in 5 years PAM enlarged in 26% and transformed into conjunctival melanoma in 8%. This contrasts with the AFIP series where malignant transformation occurred in 32% overall and in 42% if there were PAM with atypia. Multivariate analysis showed that the most significant factor for PAM enlargement was excision elsewhere before referral. The most significant for both PAM recurrence and progression to melanoma was extent of the pigmentation in clock hours.
Conclusions::
Using less stringent criteria for clinical diagnosis, conjunctival PAM is more common that previously believed and many cases may remain undetected. In contrast to much quoted histopathologic data from the AFIP, this clinicopathologic study suggested that PAM progression to melanoma is much lower. Most cases are small and subtle and do not require excision or biopsy.
Keywords: conjunctiva • melanoma • pathology techniques