Oncology & Hematology Coding Alert

See how your answers to the quiz match with the experts’.

Have you nailed down proper ICD-10-CM 2018 Merkel cell carcinoma coding? Check your progress by reviewing the answers to the quiz on page 51.

Answer to question 1:  D. ICD-10-CM code C4A.31.

Rationale: ICD-10-CM is more site specific for coding Merkel cell carcinoma of the face. While ICD-9-CM used to offer just one code for Merkel cell carcinoma of the face, (i.e. 209.31, Merkel cell carcinoma of the face), ICD-10-CM has 10 options. You select a code based on which part of the face was specifically involved. These options include:

• C4A.0, Merkel cell carcinoma of lip
• C4A.10, Merkel cell carcinoma of unspecified eyelid, including canthus
• C4A.20, Merkel cell carcinoma of unspecified ear and external auricular canal
• C4A.30, Merkel cell carcinoma of unspecified part of face
• C4A.39, Merkel cell carcinoma of other parts of face
• C4A.11, Merkel cell carcinoma of right eyelid, including canthus
• C4A.12, Merkel cell carcinoma of left eyelid, including canthus
• C4A.21, Merkel cell carcinoma of right ear and external auricular canal
• C4A.22, Merkel cell carcinoma of left ear and external auricular canal
• C4A.31, Merkel cell carcinoma of nose

Besides being site specific, ICD-10-CM offers specific codes for the right and left sides for Merkel cell carcinomas of bilateral structures like eyelids and ears. For Merkel cell carcinoma of the right and left eyelid, you look at ICD-10-CM codes C4A.11 and C4A.12, respectively. Similarly, for the right and left ears and external auricular canals, you have codes C4A.21 and C4A.22, respectively.

What  if  your  physician  does  not  specify  site? If your physician does not specify the site of the Merkel cell carcinoma on the face, you submit ICD-10-CM code C4A.30 (Merkel cell carcinoma of unspecified part of face).

Answer to question 2: A. You report code C4A.39 for Merkel cell carcinoma of scalp.

Here’s why: The ICD-10-CM code C4A.39 applies to Merkel cell carcinoma of other parts of face. Do not confuse scalp to be part of the face. Though the forehead is part of the face, scalp is said to begin on the upper edge of the forehead along the beginning of the hairline.

Statements B, C, and D are correct. ICD-9-CM used to offer a single code for Merkel cell carcinoma of the scalp and neck, (i.e. 209.32, Merkel cell carcinoma of the scalp and neck) and this maps to ICD-10-CM code C4A.4 (Merkel cell carcinoma of scalp and neck). Like the old ICD-9-CM option, you report the ICD-10-CM code C4A.4 for Merkel cell carcinoma of the scalp and neck.

Answer to question 3: C. ICD-10-CM code C4A.71.

Laterality is key for limb locations: When you report Merkel cell carcinoma of the upper or lower limbs in ICD-10-CM, you should bear in mind that ICD-10-CM has specific options based upon whether the right or the left limb was involved.

For instance, you have C4A.71 (Merkel cell carcinoma of right lower limb, including hip) and C4A.72 (Merkel cell carcinoma of left lower limb, including hip), for the right and left lower limbs respectively. You have an additional ICD-10-CM option of C4A.70 (Merkel cell carcinoma of unspecified lower limb, including hip) which you can report when your physician does not specify if the right or left lower limb was involved.

Tip: You apply same rules to Merkel cell carcinoma of the upper limb. You have the following three codes:

• C4A.61 (Merkel cell carcinoma of right upper limb, including shoulder)
• C4A.62 (Merkel cell carcinoma of left upper limb, including shoulder)
• C4A.60 (Merkel cell carcinoma of unspecified upper limb, including shoulder).

Code  descriptor: Besides being specific for laterality, the ICD-10-CM options offer more specific code descriptors. The descriptors for the lower limb codes, C4A.71, C4A.72, and C4A.70 clearly specify that these codes also apply to hips in addition to the lower limbs. Similarly, the codes for Merkel cell carcinoma in the upper limb (C4A.61, C4A.62, and C4A.60) apply to shoulder as well as the upper limb.

Answer to question 4: B. C4A.52.

ICD-10-CM gets specific again: For Merkel cell carcinoma of the trunk, you can report:

• C4A.51, Merkel cell carcinoma of anal skin
• C4A.52, Merkel cell carcinoma of skin of breast
• C4A.59, Merkel cell carcinoma of other part of trunk.

Answer to question 5: A. True.

Reason: Check out C4A.8 (Merkel cell carcinoma of overlapping sites).