"An Exploratory Journey into the Fibrillating World of Rare Cancers in Flocks" Polypoid uterine leiomyosarcomas (PUL) are a rare and poorly understood type of cancer that affects the uterus of sheep. As a veterinary pathologist, I embarked on an adventure to uncover the secrets behind this enigmatic disease, delving into the intriguing world of sheep uterine tumors.