We have comprehensively characterized the mutational landscape of eccrine poroma (EP) and eccrine porocarcinoma (EPC), uncovering novel molecular events and delineating different pathways of tumorigenesis underlying these tumours. EPs are driven largely by oncogenic fusion genes, whereas EPCs are driven largely by somatic mutations affecting various pathways, with a subset driven by fusion genes as the first oncogenic driver, and somatic mutations representing secondary events contributing to progression of the tumour. Fusion genes in EP predominantly involve YAP1, while those in EPC preferentially involve PAK gene family members.