General Surgery Coding Alert

Malignant and in situ are different.

Most conditions report to a single code family in ICD-10-CM — but not melanoma. In fact, you’ll need to get familiar with multiple code families if you want to get your melanoma diagnosis right.

Turn Here for Primary Malignant Melanoma

You’ll probably find the correct code for the bulk of your melanoma cases by turning to C43 (Malignant melanoma of skin). Within this code family, the fourth digit indicates body site, such as C43.1- (Malignant melanoma of eyelid, including canthus) or C43.7- (Malignant melanoma of lower limb, including hip).

The fifth digit for many of these codes indicates laterality, such as the following:

• C43.10 — Malignant melanoma of unspecified eyelid, including canthus
• C43.11 — Malignant melanoma of right eyelid, including canthus
• C43.12 — Malignant melanoma of left eyelid, including canthus.

In other cases, the fifth digit adds other site specificity, such as the following:

• C43.30 — Malignant melanoma of unspecified part of face
• C43.31 — Malignant melanoma of nose
• C43.39 — Malignant melanoma of other parts of face.

Look for stage: “If the report you’re coding from indicates any melanoma stage I-IV for the primary tumor, you should be using the C43 code family to report the condition,” says Marcella Bucknam, CPC, CPC-I, CCS-P, CPC-H, CCS, CPC-P, COBGC, CCC, internal audit manager with PeaceHealth in Vancouver, Wash. 

In Situ is Different

When the documentation indicates that the melanoma is isolated to the epidermis, the condition is called “in situ” melanoma or stage 0 melanoma. In those cases, you should not report the diagnosis as C43.--.

Do this: Turn to a different code family for melanoma in situ — D03 (Melanoma in situ). Similar to the C43 family, you’ll select the appropriate code from this family based on tumor site and laterality using four or five digit codes such as the following:

• D03.11 — Melanoma in situ of right eyelid, including canthus
• D03.62 — Melanoma in situ of left upper limb, including shoulder
• D03.8 — Melanoma in situ of other sites.

Coder tips: Code C43 excludes melanoma in situ using an “Excludes1” note, indicating that you should never report C43 and D03 at the same time. ICD-10-CM uses Excludes 1 notes when two conditions cannot occur together, such as a congenital form and an acquired form of the same condition. In this case, either the melanoma is in situ or it is malignant.

Look Elsewhere for Secondary Metastatic Tumor

Because melanoma can metastasize to lymph nodes and other organs, you might face coding a secondary melanoma at a site other than skin. When that’s the case, you should turn to one of the following codes:

• C77 — Secondary and unspecified malignant neoplasm of lymph nodes
• C78 — Secondary malignant neoplasm of respiratory and digestive organs
• C79 — Secondary malignant neoplasm of other and unspecified sites.

Note that all codes from these families require a fourth and/or fifth digit to further specify site, such as the following examples:

• C77.3 — Secondary and unspecified malignant neoplasm of axilla and upper limb lymph nodes
• C78.01 — Secondary malignant neoplasm of right lung
• C79.31 — Secondary malignant neoplasm of brain.