ICD-10 Code H21.34 – Primary cyst of pars plana (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H21.34 – Primary cyst of pars plana
What it is
H21.34 identifies a primary cyst of the pars plana, a benign cystic lesion in the eye’s ciliary body region. Use it when documentation specifically names a primary pars plana cyst.
Clinical signs
Clinical features vary; refer to documentation. It may be found on eye examination or imaging as a cystic structure in the pars plana, sometimes without symptoms.
When to use this code
Use this code when the provider documents a primary cyst of the pars plana or a clearly equivalent diagnosis. It is appropriate for confirmed ocular cysts in this location, even if discovered incidentally. Check documentation if the note only says “cyst of the eye” or gives an uncertain site.
Do not use for
Do not use this code for other iris, ciliary body, or choroidal cysts, or for nonspecific ocular cysts without pars plana documentation. Check documentation.
Coding tip
Code only when the record identifies the pars plana as the primary site; otherwise, query for a more specific diagnosis.