2006 ICD-9-CM Volume 1 Diagnosis Codes Home > Neoplasms 140-239 > Malignant Neoplasm Of Digestive Organs And Peritoneum 150-159 > ICD-9-CM Diagnosis 158 Malignant neoplasm of retroperitoneum and peritoneum 158 is a non-specific code that cannot be used to specify a diagnosis ICD-9-CM Diagnosis 158.0 Malignant neoplasm of retroperitoneum A primary or metastatic malignant neoplasm involving the retroperitoneum. The vast majority of cases are carcinomas, lymphomas, or sarcomas.--2004 158.0 is a specific code that can be used to specify a diagnosis ICD-9-CM Diagnosis 158.8 Malignant neoplasm of specified parts of peritoneum 158.8 is a specific code that can be used to specify a diagnosis ICD-9-CM Diagnosis 158.9 Malignant neoplasm of peritoneum unspecified 158.9 is a specific code that can be used to specify a diagnosis