The Diagnostic Usefulness of Ultrasound-Guided Peritoneal Biopsy for the Solitary Peritoneal Thickening of an Unknown Cause Visualized as Only Infiltrated Fat Tissue on a CT Scan

Purpose: To assess the usefulness of an ultrasound (US)-guided peritoneal biopsy for the solitary peritoneal thickening visualized as only infiltrated fat on a computed tomography (CT) scan. Materials and Methods: This retrospective study included 36 patients (16 males, 20 females; mean age, 51.7 years) who underwent a US-guided biopsy for the solitary peritoneal thickening of unknown cause visualized as only infiltrated fat without an apparent mass formation on a CT scan. The rate of the specific histopathological diagnosis and accuracy for the diagnosis of malignant disease was assessed. Results: The procedure was technically successful with the acquisition of an adequate amount of the specimen for microscopic examination from all patients. A specific histopathological diagnosis was made in 31/36 patients (86.1%): peritoneal carcinomatosis in 15/31 (48.4%), tuberculous peritonitis in 15/31 (48.4%) and panniculitis in 1/31 (3.2%). A non-specific histopathological diagnosis was made in 5/36 (13.9%): chronic inflammation in 4/5 (80%) and mesothelial hyperplasia in 1/5 (20%). The procedure showed sensitivity of 83.3%, with a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 85.7%, and an accuracy rate of 86.1% for the diagnosis of malignant diseases. Conclusion: The US-guided peritoneal biopsy is a fairly accurate diagnostic procedure for the peritoneal thickening visualized as only infiltrated fat on a CT scan, and it can be used before performing laparoscopic or an open biopsy.