Primary rhabdoid melanoma with clonal recurrence.

Melanoma with rhabdoid features is an uncommon melanoma variant. Many questions remain regarding rhabdoid differentiation and whether this phenotype represents a common pathogenetic pathway from distinct tissue malignancies. We describe a case of primary melanoma illustrating rhabdoid features, a recurrent rhabdoid clone and its diagnostic challenges. Immunohistochemistry in this tumor frequently involves loss of melanoma specific markers, while Vimentin may display a paranuclear accentuation in keeping with reported ultrastructural features. This case documents rhabdoid differentiation within a primary tumor and recurrence of the presumed more aggressive rhabdoid clone.