Pathology/Lab Coding Alert

Question: The pathology report for a skin lesion states "Clark's nevus" as the diagnosis. What ICD-9 code should I use?

Tennessee Subscriber

Answer: "Clark's nevus" is another term for an atypical mole (AM). Physicians also sometimes call AMs active junctional nevi, atypical melanocytic nevi, B-K moles, dysplastic nevi, and dysplastic moles.

Unlike common moles, AMs vary in color, ranging from tan to dark brown shades on a pink background. They have irregular borders that may include notches. Although technically an AM is "pre-cancerous" -- meaning that it is more likely to turn into a melanoma than a regular mole -- pathologists consider it a benign neoplasm, and you should code the diagnosis as such.

For the diagnosis, choose a code in ICD-9 category 216 based on the specific site of the Clark's nevus. For example, if the AM appears on the patient's cheek, code it 216.3 (Benign neoplasm of skin of other and unspecified parts of face).

Exception: If the nevus is on the skin of the genital organs, you'll have to look to a different category. You'll select a code from 221 (Benign neoplasm of other female genital organs) or 222 (Benign neoplasm of male genital organs).