ICD-10-CM>C00-D49>D10-D36>D20D20Benign neoplasm of soft tissue of retroperitoneum and peritoneumNon-Billable/Non-SpecificType 1 Excludesbenign lipomatous neoplasm of peritoneum and retroperitoneum (D17.79)benign neoplasm of mesothelial tissue (D19.-)CodesD20.0Benign neoplasm of soft tissue of retroperitoneumD20.1Benign neoplasm of soft tissue of peritoneum