Melanoma with rhabdomyosarcomatous differentiation: two further cases of a rare pathologic pitfall.

We describe 2 new cases of malignant melanoma with divergent rhabdomyoblastic differentiation occurring in adult patients. The patients were women aged 67 and 51 years with primary cutaneous and uterine cervical melanoma, respectively. Rhabdomyoblastic differentiation in melanoma is very rare in adult patients, and to our knowledge, only 7 such cases have been described in the world literature, of which only 4 have conclusive documentation of the presence of rhabdomyoblastic differentiation. We present the fifth and sixth cases of adult melanomas with conclusive divergent rhabdomyoblastic differentiation, including the first noncutaneous (cervical) case; we also review the literature and highlight the potential for underrecognition of this phenomenon.