Secondary Tumors and Tumorlike Lesions of the Peritoneal Cavity: Imaging Features with Pathologic Correlation

Contribution of Tc-99m RBC SPECT/ CT in Intrahepatic and Peritoneal Splenosis Mimicking Malignancy

“…Although abdominal splenosis is frequently asymptomatic, it can present with hemorrhage, pain secondary to infarction or torsion, or obstruction of the intestinal or urinary tract [1,4]. They can be confused with other entities including peritoneal carcinomatosis, endometriosis, renal cancer, abdominal lymphomas, metastatic disease and hepatic adenomas [5][6][7][8][9][10][11][12]. Sonographic and radiological fi ndings are not specifi c in splenosis, so ultrasound, CT, and MRI show limited value in the diagnostic management of abdominal splenosis [7].…”

Role of Imaging in Peritoneal Surface Malignancies

“…In disease state, fluid collects in well-defined areas of stasis, in the deep peritoneal recesses of the pelvis, the right lower quadrant (near the termination of the small bowel mesentery at the ileocecal junction), the superior aspect of the sigmoid mesocolon, and the right paracolic gutter [6].…”

“…Imaging shows well circumscribed to ill-defined lesions along the surface of liver and spleen forming bi-convex deposits. Scalloping of the visceral surfaces of the intraperitoneal organs is an important diagnostic finding that helps differentiate pseudomyxoma from simple ascites [6]. Differentiating the true PMP from mucinous carcinomatosis at CT alone is difficult because their CT findings overlap despite their different pathologic features and clinical course.…”

“…Differentiating the true PMP from mucinous carcinomatosis at CT alone is difficult because their CT findings overlap despite their different pathologic features and clinical course. [6] Mucinous carcinomatosis tends to involve the chest more frequently with effusions or pleural masses and may also be accompanied by mesenteric or retroperitoneal lymphadenopathy, omental caking, and invasion into parenchymal organs [39].…”

Mucin stratification in pseudomyxoma peritonei: a pathognomonic ultrasonographic sign

“…The ascitic fluid typically shows echogenic septations with a marked laminated appearance (the 'onion-skin' effect), reflecting concentric layering of mucin in the peritoneal cavity, typical of viscous or gelatinous fluid. The septations (borders of mucinous nodules), along with the observable fluid stratification, are relatively pathognomonic of PMP, although both have been described occasionally in other forms of infective ascites and in rare primary peritoneal malignancies 9 . Dedicated ultrasound scanning is effective in differentiating disorders in patients presenting with ascites and disseminated peritoneal implants.…”