Lymph node melanosis from a primary cutaneous lesion combining a nodular (tumoral) melanosis and a congenital dermal melanocytic nevus.

Tumoral or nodular melanosis is considered as a rare manifestation of a completely regressed melanoma whose histopathological features include confluent dermal nodular aggregates of heavily melanized polygonal cells consistent with melanophages. Tumoral melanosis involving also lymph node is an even rarer event that has been reported only twice in the literature. We report a case of lymph node melanosis in the sentinel lymph node draining from a primary cutaneous lesion combining a dermal tumoral melanosis consistent with a complete regressed melanoma associated with a residual part of a deep congenital nevus. We discuss the histopathological diagnosis of our primary cutaneous lesion and the sentinel lymph node microscopic findings, compare our case with the previous ones, and discuss the possible prognostic and therapeutic implications.