ICD-10 Code H21.359 – Exudative cyst of pars plana, unspecified eye (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.359 – Exudative cyst of pars plana, unspecified eye
What it is
This code identifies an exudative cyst of the pars plana, with no eye laterality specified. It refers to a fluid-filled lesion in the ciliary body region; check documentation for the exact clinical description.
Clinical signs
Findings may include a cystic lesion seen on ocular examination or imaging, sometimes discovered incidentally. Clinical features vary; refer to documentation for symptoms, eye laterality, and whether the lesion is active or stable.
When to use this code
Use H21.359 when the clinician documents an exudative cyst of the pars plana and does not specify right or left eye. It is also appropriate when the record confirms the diagnosis but gives no further laterality detail. Do not infer the eye from context unless documentation is clear.
Do not use for
Do not use this code for other iris, ciliary body, or choroidal cysts, or for nonspecific eye cysts without pars plana involvement. If the note describes a different lesion type, check documentation.
Coding tip
Always verify laterality first; if the chart specifies right or left eye, choose the more specific code instead of H21.359.