ICD-10 Code D48.3 – Neoplasm of uncertain behavior of retroperitoneum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D48.3 – Neoplasm of uncertain behavior of retroperitoneum
What it is
D48.3 identifies a retroperitoneal mass or tumor whose behavior is uncertain. Use it when pathology or clinical documentation does not confirm the lesion is clearly benign or malignant.
Clinical signs
Clinical features vary; refer to documentation. Retroperitoneal lesions may be found on imaging, during surgery, or after evaluation of a nonspecific abdominal or back mass.
When to use this code
Use D48.3 when the provider documents a neoplasm of uncertain behavior in the retroperitoneum, including a mass that has not been definitively classified. It may also apply when biopsy or imaging suggests an indeterminate tumor and final behavior is not stated. Check documentation if the site is described more broadly than retroperitoneum.
Do not use for
Do not use this code for clearly benign or malignant retroperitoneal tumors. If the record only describes symptoms, a cyst, or an unspecified abdominal mass, choose the documented diagnosis instead.
Coding tip
Code D48.3 only when the retroperitoneal location and uncertain behavior are both documented.