ICD-10 Code C38.2 – Malignant neoplasm of posterior mediastinum (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C38.2 – Malignant neoplasm of posterior mediastinum
What it is
C38.2 identifies a malignant tumor arising in the posterior mediastinum, the space in the chest behind the heart and between the lungs. Use it when documentation names this anatomic site and confirms cancer.
Clinical signs
Clinical features vary; refer to documentation. Patients may present with chest pain, cough, dyspnea, or symptoms from compression of nearby structures, but the coded diagnosis should be based on the documented malignant neoplasm.
When to use this code
Use C38.2 when the provider documents a primary or malignant tumor specifically located in the posterior mediastinum. It also fits pathology, imaging, or operative notes that clearly identify this site. If the record only says “mediastinal mass,” check documentation before assigning the code.
Do not use for
Do not use this code for benign mediastinal masses, unspecified mediastinal neoplasms, or tumors in other mediastinal compartments. If the site is unclear or another primary site is documented, code the documented condition instead.
Coding tip
Verify both malignancy and exact posterior mediastinal location in the record before coding.