Giant Cyst with Unclear Positioning and Undefined Pathological Diagnosis

This is the report of a right-sided giant cystic lesion of a young woman without symptoms which was diagnosed incidentally during routine health screening before marriage. All the routine blood tests and chest x-ray were normal. Abdominal ultrasound (US) revealed a type-3 hydatic cyst in the right liver lobe, but serum tests were negative. On the contrary, Magnetic Resonance Imaging (MRI) revealed a “retroperitoneal cyst” adjacent to the right upper pole of the kidney rising upwards by making a massive bulge at the posterior part of the right lobe of the liver, displacing and rotating the right lobe through the diaphragm by neighboring liver segments of VI, VII, and VIII. At the operation, it was unexpectedly discovered that none of the abdominal US and MRI radiologic reports were wholly true or false! As a well-known fact, without any exception of its anatomical structures, a normal liver is located completely intraperitoneal part of the abdominal cavity. This case is the first where we could not find another in the searched literature that the upper inferior part of the right lobe of the liver was located “partially” in the retroperitoneal area. As there was no trauma history of the patient, this might be a congenital malformation affecting both the right liver lobe and right side of the diaphragm in which a giant fully retroperitoneal cyst was originated. All of the radiologic, surgical, and postoperative pathological diagnostic uncertainty and confusion is caused by this malformation.