ICD-10 Code C84.05 – Mycosis fungoides, lymph nodes of inguinal region and lower limb (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code C84.05 – Mycosis fungoides, lymph nodes of inguinal region and lower limb
What it is
C84.05 identifies mycosis fungoides with involvement of the inguinal lymph nodes and lower limb nodes. Use it when documentation clearly states this specific cutaneous T-cell lymphoma pattern.
Clinical signs
Findings may include persistent skin plaques or tumors with regional lymph node involvement in the groin or leg. Clinical features vary; refer to documentation for confirmed nodal site and disease extent.
When to use this code
Use this code when the provider documents mycosis fungoides and specifies lymph node involvement in the inguinal region and lower limb. It also fits records that identify regional nodal disease at these sites without a different, more specific lymphoma code.
If the note only says mycosis fungoides without nodal location, check documentation. Code selection should match the stated anatomic involvement, not assumptions from imaging or exam alone.
Do not use for
Do not use it for mycosis fungoides without documented inguinal or lower-limb lymph node involvement. It is also wrong for other cutaneous lymphomas or unspecified lymphadenopathy.
Coding tip
Confirm the exact nodal region in the provider note before assigning C84.05.