Cutaneous Malignant Melanoma With Rhabdomyosarcomatous Dedifferentiation: an Immunohistological and Molecular Case Study With Literature Review.

Cutaneous malignant melanoma can show a wide range of cytomorphological variability, in particular exhibiting a rhabdoid appearance is not uncommon in melanoma cells; however, the phenomenon of "dedifferentiation" with loss of melanocytic immunohistochemical properties and expression of skeletal muscle immunomarkers is exceedingly rare. Owing to the rarity of such melanomas, their clinicopathological features and molecular profile remain largely unknown. In this report, we describe the clinical, immunomorphological, and molecular features of melanomas with rhabdomyosarcomatous dedifferentiation by presenting a new case and exploring the literature for the previously reported cases.