Verrucous carcinoma and Syringocystadenoma papilliferum of thigh-An unusual collision tumor

Collision tumor is an entity used to describe the occurrence of two separate primary tumors at one anatomic location. Collision tumors occur at different locations in the body including skin. Syringocystadenoma papilliferum (SP) is an adnexal tumor of apo-eccrine differentiation and is juxtaposed to a nevus in one third of the cases and to a basal cell carcinoma in 10% of the cases. We report an unusual collision of SP and verrucous carcinoma occurring at an unusual location.