Benign neoplasm of mesothelial tissue of peritoneum

This code signifies a non-cancerous growth originating from the mesothelial lining of the abdominal cavity. These tumors are typically slow-growing and do not metastasize, distinguishing them from malignant mesotheliomas. The peritoneum is the serous membrane that forms the lining of the abdominal cavity and covers most of the abdominal organs.

Assign this code when documentation confirms a benign neoplasm specifically located in the peritoneal mesothelial tissue. This often follows a biopsy or surgical excision with pathological confirmation of benignity. Supporting documentation should clearly state "benign mesothelial tumor of peritoneum" or similar.

• Differentiate carefully from malignant mesotheliomas (C45.-) which are aggressive cancers.
• Ensure the pathology report explicitly states "benign" and specifies "mesothelial tissue" and "peritoneum."
• Do not use for benign neoplasms of other abdominal organs; those have specific codes based on their anatomical site.