ICD-10-CM>C00-D49>C45-C49>C48C48Malignant neoplasm of retroperitoneum and peritoneumNon-Billable/Non-SpecificType 1 ExcludesKaposi's sarcoma of connective tissue (C46.1)mesothelioma (C45.-)CodesC48.0Malignant neoplasm of retroperitoneumC48.1Malignant neoplasm of specified parts of peritoneumC48.2Malignant neoplasm of peritoneum, unspecifiedC48.8Malignant neoplasm of overlapping sites of retroperitoneum and peritoneum