Secondary carcinoid tumors of peritoneum

This code signifies the presence of metastatic neuroendocrine tumors, specifically carcinoid, that have spread to the peritoneum from a primary site elsewhere in the body. These tumors originate from enterochromaffin cells and are characterized by their ability to produce bioactive substances. The peritoneum is involved as a secondary site, indicating dissemination of the original carcinoid malignancy.

Apply this code when documentation clearly states secondary or metastatic carcinoid tumor involvement of the peritoneum. This typically occurs in patients with a known primary carcinoid tumor (e.g., in the gastrointestinal tract or lung) who subsequently develop peritoneal implants. Supporting documentation includes pathology reports confirming carcinoid histology in peritoneal biopsies, imaging studies showing peritoneal carcinomatosis, and physician notes explicitly identifying peritoneal metastasis.

• Always code the primary malignant neoplasm first, followed by this code for the secondary site.
• Distinguish carefully between primary peritoneal tumors and secondary metastases; this code is exclusively for secondary involvement.
• Ensure the documentation specifies "carcinoid" histology; other types of neuroendocrine tumors may have different codes.