ICD-10 Code J98.59 – Other diseases of mediastinum, not elsewhere classified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code J98.59 – Other diseases of mediastinum, not elsewhere classified
What it is
This code identifies mediastinal disorders that do not fit a more specific ICD-10-CM category. Use it for documented disease processes in the mediastinum when the record does not name a better code.
Clinical signs
Clinical features vary; refer to documentation. Patients may have chest discomfort, cough, dyspnea, or findings from imaging that show an abnormal mediastinal process.
When to use this code
Use J98.59 when the provider documents a mediastinal disease or disorder and no more specific code applies. It is appropriate for nonspecific or unusual mediastinal conditions recorded in the chart. If the note only describes a mass, lesion, or cyst, check documentation for the exact diagnosis before assigning this code.
Do not use for
Do not use this code for a clearly identified mediastinal mass, tumor, or cyst when a more specific code is available. Do not use it when the condition is actually a lung, pleural, or cardiac disorder.
Coding tip
Code from the provider’s exact wording, and query when the mediastinal condition is described only by imaging or is not fully specified.