ICD-10 Code D37.5 – Neoplasm of uncertain behavior of rectum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D37.5 – Neoplasm of uncertain behavior of rectum
What it is
This code identifies a rectal neoplasm whose behavior is uncertain, meaning the pathology or clinical picture does not clearly show benign or malignant behavior. Use it when documentation states uncertain behavior for a rectal lesion.
Clinical signs
Clinical features vary; refer to documentation. Patients may have a rectal mass, bleeding, altered bowel habits, or be found on endoscopy or imaging with a lesion requiring further evaluation.
When to use this code
Use D37.5 when the provider documents a rectal tumor, polyp, or mass as having uncertain behavior, or when pathology cannot definitively classify it as benign or malignant. It also fits cases under surveillance or additional workup when the record supports uncertain behavior. Check documentation if the site is rectal but the behavior is not stated.
Do not use for
Do not use this code for clearly benign rectal lesions or for confirmed malignant rectal neoplasms. If the documentation names carcinoma, dysplasia, or another specific diagnosis, code that condition instead.
Coding tip
Verify both site and behavior in the report before assigning D37.5.