Malignant neoplasm of peritoneum, unspecified

This code signifies a primary cancerous tumor originating in the peritoneum, the membrane lining the abdominal cavity and covering its organs. The specific location or type of peritoneal malignancy is not further defined within the medical record.

Apply this code when documentation clearly indicates a malignant neoplasm of the peritoneum, but the precise anatomical site within the peritoneum (e.g., parietal, visceral, omentum) is not specified by the provider. This code is appropriate when the pathology report confirms malignancy but lacks further detail regarding the exact origin within the peritoneal cavity.

• Do not use this code if a more specific site within the peritoneum (e.g., C48.0 for retroperitoneum, C48.1 for specified parts of peritoneum) is documented.
• Always review pathology reports and operative notes for greater specificity regarding the tumor's origin.
• Sequence this code as the primary diagnosis when the peritoneal malignancy is the reason for the encounter, followed by any associated conditions or complications.