Peritoneal surface malignancies represent a heterogeneous group of primary and secondary neoplasms, most commonly arising from metastatic carcinomas of gastrointestinal or ovarian origin that spread to the peritoneum. This peritoneal dissemination is known under the generic term of peritoneal carcinomatosis and its clinical presentation is insidious, so it may be an incidental finding in patients undergoing CT scans for non-specific symptoms, such as abdominal distension or mild abdominal pain.

When dealing with peritoneal carcinomatosis of unknown origin, histological diagnosis is a priority in order to apply the appropriate treatment. The omentum is one of the preferred sites for peritoneal seeding, so percutaneous omental biopsy represents an essential tool in this scenario.

In this educational poster, we review the technique, indications and efficacy of US-guided omental biopsy, based on the existing literature and our 15 years of experience at a referral centre for peritoneal surface malignancies.