ICD-10 Code D09.20 – Carcinoma in situ of unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code D09.20 – Carcinoma in situ of unspecified eye
What it is
D09.20 identifies carcinoma in situ involving the eye when the exact site is not specified. This means abnormal cells are present in the eye tissue but have not invaded deeper structures.
Clinical signs
Clinical features vary; refer to documentation. You may see a recorded diagnosis based on ophthalmic examination, biopsy, or pathology confirming in situ disease without invasion.
When to use this code
Use D09.20 when the provider documents carcinoma in situ of the eye and does not name a more specific ocular site. It also fits when the record confirms noninvasive malignant change but the laterality or exact eye structure is not stated. Check documentation if the note is unclear.
Do not use for
Do not use this code for invasive malignant eye tumors or for benign, dysplastic, or suspicious lesions without confirmed carcinoma in situ. If the documentation specifies a different ocular site, code that site instead.
Coding tip
Query for the exact eye location and whether the lesion is in situ before assigning D09.20.