ICD-10 Code C51.0 – Malignant neoplasm of labium majus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C51.0 – Malignant neoplasm of labium majus
What it is
C51.0 identifies a malignant tumor arising in the labium majus, the outer fold of the vulva. Use it when documentation specifies cancer of that exact site.
Clinical signs
Typical findings include a vulvar mass, ulceration, bleeding, pain, itching, or a nonhealing lesion. Clinical features vary; refer to documentation.
When to use this code
Use C51.0 when the provider documents primary cancer of the labium majus or a malignant neoplasm limited to that structure. It also fits pathology or operative notes that clearly name the labium majus as the site. If the site is described only as vulvar or unspecified, check documentation before coding.
Do not use for
Do not use this code for benign vulvar lesions, dysplasia, or malignant disease of other vulvar sites. If the diagnosis is unspecified vulvar cancer, choose the appropriate unspecified code instead.
Coding tip
Confirm the exact anatomic site in the pathology, operative, or oncology note before assigning C51.0.