Carcinosarcoma is also one among the rare PC, and the study performed by Bai et al. [62] with the help of LCM to isolate carcinomatous and sarcomatous cells from carcinosarcoma samples, were studied for IHC, clinicopathological, and KRAS mutation, which showed similar mutation pattern in KRAS mutation (p.G12D and p.G12V) in both the samples, indicating that both the components has a monoclonal origin. Here, KRAS is linked to pachyonychia congenita.