ICD-10 Code C12 – Malignant neoplasm of pyriform sinus (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C12 – Malignant neoplasm of pyriform sinus
What it is
C12 identifies a malignant tumor arising in the pyriform sinus, a part of the hypopharynx beside the laryngeal inlet. Use it when documentation states primary cancer of this specific site.
Clinical signs
Common findings include persistent sore throat, dysphagia, odynophagia, hoarseness, referred ear pain, or a neck mass. Clinical features vary; refer to documentation for the confirmed site and pathology.
When to use this code
Use C12 when the provider documents primary malignant neoplasm of the pyriform sinus, including biopsy-confirmed or clinically diagnosed cases. It may also apply when the site is clearly identified in operative, pathology, or oncology notes. If the record only says hypopharyngeal cancer without a precise subsite, check documentation.
Do not use for
Do not use C12 for benign lesions, dysplasia, or metastatic disease to the pyriform sinus from another primary site. If the cancer is documented elsewhere in the hypopharynx or larynx, select the more specific code.
Coding tip
Verify whether the pyriform sinus is named as the primary site before assigning C12.