Merkel cell carcinoma of scalp and neck

This code identifies a rare and aggressive neuroendocrine carcinoma of the skin, specifically originating on the scalp or neck. Merkel cell carcinoma (MCC) is characterized by rapid growth and a high propensity for local recurrence and metastasis. It typically presents as a firm, painless, shiny nodule.

Apply this code when documentation explicitly states a diagnosis of Merkel cell carcinoma located on the scalp or neck. This diagnosis is typically confirmed by biopsy and immunohistochemical staining. Use this code for both primary and recurrent tumors in these specific anatomical sites.

• Ensure the documentation clearly specifies "scalp" or "neck" as the primary site; do not use for MCC in other body areas.
• Always sequence this code as the primary diagnosis when it is the reason for the encounter, such as for excision or chemotherapy.
• Consider additional codes for any associated metastatic disease, using appropriate secondary malignancy codes.