Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 64 02 2026 04 03 11686 11686 Ali Abzirakan Aslanduz Assistant Professor, Department of Radiology, Tabriz University of Medical Sciences, Tabriz, Iran. Javad Jalili Associate Professor, Department of Radiology, Tabriz University of Medical Sciences, Tabriz, Iran. Shahab Abdi Assistant Professor, Department of Radiology, Tabriz University of Medical Sciences, Tabriz, Iran. Shalaleh Aghaei MD, Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran. 2025 05 31 2025 12 15 Primary peritoneal hydatidosis is a rare form of cystic echinococcosis characterized by peritoneal involvement without prior hepatic or pulmonary disease. This condition may present with non-specific symptoms such as abdominal pain or distention and is frequently misdiagnosed due to its radiologic similarity to other intra-abdominal cystic pathologies. In this report, we describe a 37-year-old man with no relevant past medical history who presented with diffuse intra-abdominal cystic lesions initially suggestive of pseudomyxoma peritonei. Imaging, particularly computed tomography, revealed numerous non-enhancing cystic lesions throughout the peritoneal cavity, raising the suspicion of disseminated cystic disease. Surgical exploration and histopathological examination confirmed the diagnosis of primary peritoneal hydatidosis. This case underscores the importance of considering hydatid disease in the differential diagnosis, particularly in endemic regions. https://acta.tums.ac.ir/index.php/acta/article/view/11686 https://acta.tums.ac.ir/index.php/acta/article/download/11686/6023