Malignant neoplasm of specified parts of peritoneum

This code signifies a primary malignant tumor originating in specific, named anatomical regions of the peritoneum, such as the parietal, visceral, or pelvic peritoneum. It indicates a cancerous growth that has developed directly within these peritoneal tissues, rather than a metastasis from another primary site.

Use this code when documentation clearly identifies a primary malignant neoplasm arising from a specified part of the peritoneum. This is appropriate for conditions like primary peritoneal carcinoma or mesothelioma of the peritoneum, where the origin is definitively traced to the peritoneal lining itself. Documentation must specify the primary nature and the exact peritoneal location.

• Differentiate carefully between primary peritoneal malignancy and metastatic disease to the peritoneum; the latter would typically use a secondary neoplasm code.
• Ensure the physician's documentation specifies "primary" and the particular peritoneal site (e.g., parietal, visceral, pelvic) to support this code.
• Avoid using this code for unspecified peritoneal malignancy; a more general code for unspecified peritoneum (C48.2) or unspecified site (C48.8) may be more appropriate if the specific part is not documented.