ICD-10 Code D48.4 – Neoplasm of uncertain behavior of peritoneum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D48.4 – Neoplasm of uncertain behavior of peritoneum
What it is
D48.4 identifies a peritoneal growth whose behavior is uncertain, meaning pathology or clinical findings do not clearly show whether it is benign or malignant. Use it when the record documents an uncertain neoplasm in the peritoneum.
Clinical signs
Clinical features vary; refer to documentation. Patients may have an abdominal or pelvic mass, pain, distention, or findings on imaging or surgery that suggest a peritoneal lesion needing further evaluation.
When to use this code
Use D48.4 when the provider documents a neoplasm of uncertain behavior involving the peritoneum and no more specific diagnosis is established. It is appropriate for pathology, operative, or imaging reports that describe uncertain biologic behavior. If the record later confirms benign or malignant disease, you should code that diagnosis instead.
Do not use for
Do not use this code for clearly benign peritoneal lesions or for confirmed malignant neoplasms of the peritoneum. Check documentation if the site is another abdominal structure or if the behavior is not stated.
Coding tip
Code the documented behavior and site exactly as stated; if uncertainty is only implied, query for clarification.