Histologic features of conjunctival melanoma predictive of metastasis and death (an American Ophthalmological thesis).

Purpose: In conjunctival melanoma, tumor thickness and nonlimbal location are associated with poor prognosis. However, other established high-risk features for cutaneous melanoma, including ulceration, mitotic figures, epithelioid cell type, and lymphovascular invasion, have not previously been studied extensively for their prognostic value in conjunctival melanoma. We examined the hypothesis that these features also predict regional nodal metastasis and death in conjunctival melanoma.

Methods: The medical records of 44 of 46 consecutive conjunctival melanoma patients treated between June 2003 and December 2009 were retrospectively reviewed; tumor tissue was not available for the two excluded patients. Demographic and clinicopathologic features, including tumor location, tumor thickness, ulceration, mitotic rate, histology, lymphovascular invasion, and microsatellitosis, were reviewed. Outcome measures included regional nodal metastasis, distant metastasis, and death.

Results: Twenty-six women and 18 men had a median age of 62 years. Regional nodal metastasis occurred in 7 patients (16%) and distant metastasis in 9 (20%). Median follow-up was 40 months. At last follow-up, 10 patients (23%) had died of disease. Tumor thickness>2.0 mm, ulceration, and mitotic figure>1/mm2 predicted regional nodal metastasis and death from disease. In addition to these three histologic features, vascular invasion, epithelioid cell type, and microsatellitosis significantly predicted death from disease. Tumor location (bulbar vs nonbulbar) was not correlated with regional nodal metastasis or death.

Conclusions: In conjunctival melanoma, as in cutaneous melanoma, thicker tumor, ulceration, and higher mitotic rate are correlated with regional nodal metastasis. In addition, lymphovascular invasion, epithelioid cell type, and microsatellitosis are correlated with melanoma-related death.