Malignant neoplasm of retroperitoneum and peritoneum (C48)

ICD-10 code C48 covers malignant tumors affecting the retroperitoneum and peritoneum, areas in the abdominal cavity. These codes are specifically used to classify cancers originating in these regions, including various specialized forms of retroperitoneal and peritoneal malignancies.

The section includes C48.0 for malignant neoplasms of the retroperitoneum, which encompass tumors such as retroperitoneal sarcomas, liposarcomas, and primary malignant neoplasms of nearby tissues like perirenal and periadrenal areas. The synonym list helps clarify that terms like "retroperitoneal sarcoma" or "primary giant cell sarcoma of retroperitoneum" all fall under this code. C48.1 codes malignant neoplasms of specific parts of the peritoneum, including the omentum, mesocolon, and rectouterine pouch (pouch of Douglas), covering various sarcomas and adenocarcinomas localized to these sites. For cases where the peritoneal site is unspecified, C48.2 is used; it covers terms linked to general malignant tumors of the peritoneum, such as primary adenocarcinoma or sarcoma. Lastly, C48.8 identifies malignant neoplasms overlapping both retroperitoneal and peritoneal sites, useful when tumors span these adjacent regions. These distinctions are crucial for correct coding of gastrointestinal cancers involving these complex anatomical sites.