[Peritoneal carcinomatosis secondary to CUP syndrome : Diagnosis and indications for multimodal treatment]. / Peritonealkarzinose beim CUP­Syndrom : Diagnostik und Indikationsstellung für die multimodale Therapie.

CLINICAL PROBLEM: Peritoneal carcinomatosis secondary to cancer of unknown primary (CUP) syndrome is a rare entity for which there are no uniform treatment recommendations or guidelines. The median survival time is 3 months. DIAGNOSIS: Computed tomography (CT), magnetic resonance imaging (MRI), and 18F­FDG positron emission tomography (PET)/CT are valid imaging modalities for the detection of peritoneal carcinomatosis. The sensitivity of all techniques is highest for large, macronodular peritoneal carcinomatosis manifestations. A limitation of all imaging techniques is limited and small-nodular peritoneal carcinomatosis. Also, peritoneal metastasis in the small bowel mesentery or diaphragmatic domes can only be visualized with low sensitivity. Therefore, exploratory laparoscopy should be considered as the next diagnostic step. In half of these cases an unnecessary laparotomy can be avoided, because the laparoscopy revealed diffuse, small-nodule involvement of the small bowel wall and thus an irresectable situation. TREATMENT: In selected patients, performing complete cytoreduction followed by hyperthermic intra-abdominal chemotherapy (HIPEC) is a good therapeutic option. Therefore, the identification of the extent of peritoneal tumor manifestation as accurately as possible is important for the definition of the increasingly complex oncological therapy strategies.