ICD-10 Code D48.1 – Neoplasm of uncertain behavior of connective and other soft tissue (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D48.1 – Neoplasm of uncertain behavior of connective and other soft tissue
What it is
This code identifies a soft tissue or connective tissue growth whose behavior is not clearly benign or malignant. Use it when pathology or clinical documentation states uncertain behavior.
Clinical signs
Clinical features vary; refer to documentation. These lesions may present as a mass, swelling, or tissue abnormality, but the diagnosis depends on the provider’s assessment and pathology findings.
When to use this code
Use D48.1 when the record documents a neoplasm of connective tissue, fascia, tendon, muscle, or other soft tissue with uncertain behavior. It is appropriate when the diagnosis is confirmed but the lesion is not classified as benign or malignant. Check documentation if the site or behavior is unclear.
Do not use for
Do not use this code for clearly benign soft tissue tumors or malignant neoplasms. If the provider documents a different site or behavior, code that condition instead.
Coding tip
Confirm both the tissue type and the “uncertain behavior” wording before assigning D48.1.