Updates on Cancer of Unknown Primary – Highlights from the Congress of the European Society of Pathology (ESP) 2024 and beyond

Cancer of unknown primary (CUP) represents a heterogeneous group of metastatic epithelial or undifferentiated neoplasms where the primary tumour remains undetectable despite a standardized diagnostic evaluation. It is a rare condition accounting for less than 5% of all cancers and poses unique diagnostic and therapeutic challenges (1).