Merkel cell carcinoma of unsp ear and external auric canal

This code signifies a rare and aggressive neuroendocrine carcinoma, Merkel cell carcinoma, originating in the skin of the ear or external auditory canal. It indicates that the specific ear (left or right) has not been documented.

Apply this code when documentation confirms a diagnosis of Merkel cell carcinoma affecting the ear or external auricular canal, and laterality is not specified. This is typically used when pathology reports confirm the diagnosis but do not indicate the precise side.

• Always seek clarification from the provider if laterality (left or right ear) is not documented, as more specific codes exist.
• Do not use this code if the Merkel cell carcinoma is definitively located on a specific ear (e.g., C4A.21 for right ear).
• Sequence this code as the primary diagnosis when it is the reason for the encounter, followed by any relevant secondary diagnoses.