ICD-10 Code D19.9 – Benign neoplasm of mesothelial tissue, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D19.9 – Benign neoplasm of mesothelial tissue, unspecified
What it is
D19.9 identifies a benign, noncancerous growth arising from mesothelial tissue when the site is not specified. Use it when documentation confirms a mesothelial neoplasm but does not name a more precise location.
Clinical signs
Clinical features vary; refer to documentation. These lesions may be found as an incidental mass or cause local pressure effects, but the record should clearly describe a benign mesothelial neoplasm.
When to use this code
Use D19.9 when the provider documents a benign neoplasm of mesothelial tissue and the anatomic site is unspecified. It also fits when pathology or imaging confirms the diagnosis, but the note does not identify a more exact codeable site. Check documentation if the lesion is described as malignant, uncertain, or reactive rather than neoplastic.
Do not use for
Do not use this code for malignant mesothelioma or for benign lesions with a documented specific site that has a more precise ICD-10-CM option. Do not assign it for nonspecific effusions, inflammation, or postprocedural findings.
Coding tip
If the pathology report names the mesothelial site, code the more specific diagnosis instead of this unspecified code.