ICD-10 Code C76 – Malignant neoplasm of other and ill-defined sites (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C76 – Malignant neoplasm of other and ill-defined sites
What it is
C76 is used for malignant neoplasms in sites that are not clearly specified or do not fit a more exact anatomic code. It signals a cancer diagnosis when the record identifies an ill-defined or other site.
Clinical signs
Clinical features vary; refer to documentation. Records may describe a malignant mass, invasive growth, or cancer found in a poorly localized anatomic area without a more specific site assignment.
When to use this code
Use C76 when the provider documents a malignant neoplasm at an “other” or ill-defined site and no more specific ICD-10 code is supported. It is appropriate when the anatomic location is vague, incomplete, or not otherwise classifiable. If later documentation identifies the exact primary site, code that site instead.
Do not use for
Do not use C76 when the chart supports a specific primary site, secondary site, or metastatic site code. Check documentation if the lesion is benign, uncertain, or better described by another neoplasm category.
Coding tip
Query for the exact anatomic site before assigning C76, because a more specific cancer code is usually preferred.