Collision tumors are characterized by the coexistence of two cancers in the same
anatomical site and its pathogenesis remains controversial. Although uncommon, the
association of basal cell carcinoma and melanocytic nevus is the most common among
combinations of skin tumors. Even rarer is the association of two malignant tumors.
We report a case of tumor collision representing melanoma and basosquamous cell
carcinoma, a combination not previously described in the literature, since there are
no reported cases of melanoma with this type of basal cell carcinoma.