ICD-10 Code D09.21 – Carcinoma in situ of right eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D09.21 – Carcinoma in situ of right eye
What it is
D09.21 identifies carcinoma in situ involving the right eye. It means abnormal cells are confined to the original site and have not invaded nearby tissue.
Clinical signs
Clinical features vary; refer to documentation. Diagnosis is typically based on ophthalmic evaluation and pathology confirming a noninvasive malignant lesion in the right eye.
When to use this code
Use this code when the record specifically documents carcinoma in situ of the right eye. It is appropriate when pathology or the treating clinician confirms a noninvasive lesion limited to that eye. Check documentation if laterality or anatomic site is unclear.
Do not use for
Do not use it for invasive eye cancer, uncertain masses, or lesions documented only as suspicious. If the chart says left eye, bilateral eye, or another ocular site, code accordingly.
Coding tip
Verify both the in situ status and the right-sided laterality before assigning D09.21.