ICD-10 Code C03.1 – Malignant neoplasm of lower gum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C03.1 – Malignant neoplasm of lower gum
What it is
C03.1 identifies a malignant tumor arising in the lower gum, also called the mandibular gingiva. Use it when documentation specifies cancer of the lower gum rather than another oral site.
Clinical signs
Clinical features vary; refer to documentation. Commonly recorded findings include a persistent gum mass, ulceration, bleeding, pain, or loosening of adjacent teeth, but you should code only what is supported in the record.
When to use this code
Use this code when the provider documents primary cancer of the lower gum, including biopsy-confirmed malignant neoplasm of the mandibular gingiva. It may also apply when the note clearly localizes the tumor to the lower gum and no more specific site is stated. Check documentation if the lesion involves multiple oral structures.
Do not use for
Do not use C03.1 for benign gum lesions, inflammatory gingival disease, or cancers documented in another oral cavity site. If the chart does not clearly identify the lower gum, check documentation.
Coding tip
Code the exact anatomic site stated by the provider; if the record says “gingiva” without laterality or upper/lower detail, verify the location before assigning C03.1.