Question: A 60-year-old Caucasian man was referred to our department for restaging of cancer of unknown primary syndrome with peritoneal carcinosis (confirmed by diagnostic laparoscopy), which had been diagnosed 8 months before. The patient had already undergone 6 cycles of combination chemotherapy with fluorouracil, leucovorin, oxaliplatin, and panitumumab (FOLFOX/Vectibix) for histologic and immunohistochemical diagnosis of adenocarcinoma (colorectal type, KRAS wild type). Physical examination was unremarkable, blood tests showed a moderate anemia (hemoglobin, 11.9 g/dL), and normal differential blood count; other laboratory tests were uninformative.