Pilar cyst

This code represents a pilar cyst, also known as a trichilemmal cyst. These are benign, slow-growing epidermal cysts that typically arise from hair follicles, most commonly on the scalp. They are usually smooth, firm, and dome-shaped nodules.

Use this code when documentation explicitly identifies a pilar cyst. This diagnosis is typically made clinically, but may be confirmed by biopsy or excision. This code is appropriate for both initial diagnosis and subsequent encounters related to the management or removal of the cyst.

• Differentiate from other epidermal cysts like epidermoid cysts (L72.0) or sebaceous cysts, which are often mislabeled but are distinct entities.
• Ensure documentation specifies "pilar" or "trichilemmal" to support this specific code.
• If the cyst is infected, an additional code for the infection (e.g., L02.91 for cutaneous abscess, unspecified) should be considered.