Patterns of visceral metastasis in cutaneous melanoma: a descriptive study

Some types of cancer tend to spread to certain organs. In the case of melanoma, uveal melanoma spreads almost exclusively to the liver, while cutaneous melanoma spreads to the liver and other organs. Although important advances have been made in our understanding of the molecular mechanisms underlying melanoma, few recent studies have focused on the patterns of visceral metastasis in cutaneous melanoma. The aim of this study was to retrospectively investigate whether clinicopathologic variants of cutaneous melanoma and primary tumor site might be associated with pattern and time of onset of metastasis to visceral sites, including the central nervous system (CNS).

We included patients diagnosed with cutaneous melanoma between 1988 and 2009 with at least 2 years' follow-up.

Of the 1083 patients studied, 92 developed visceral metastasis. The CNS was affected in 21 cases, the lungs in 24, the liver in 17, the digestive tract in 7, and multiple organs simultaneously in 23. Metastasis to the lungs, the liver, and the digestive tract occurred within 5 years in most cases, while metastasis to the CNS and multiple organs occurred later (>5 years in 38% and 43% of cases, respectively).

Unlike uveal melanoma, cutaneous melanoma spreads to different organs without any particular predilection. We observed no significant associations between the site of visceral metastasis and either clinicopathologic variant or location of the primary tumor. Metastasis occurred within 5 years of diagnosis in most cases, but it can occur after 10 years.