C4A.5Merkel cell carcinoma of trunk

C4A.5 is the ICD-10-CM diagnosis code for Merkel cell carcinoma of trunk. It belongs to category C4A (Merkel cell carcinoma), block C43-C44 (melanoma and other malignant neoplasms of skin) and chapter 2 (neoplasms). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within C4A (Merkel cell carcinoma), C4A.5 is specifically for Merkel cell carcinoma of trunk. Related codes cover of lip (C4A.0), of eyelid, including canthus (C4A.1), of ear and external auricular canal (C4A.2), of other and unspecified parts of face (C4A.3), of scalp and neck (C4A.4), of upper limb, including shoulder (C4A.6), of lower limb, including hip (C4A.7), of overlapping sites (C4A.8) and 1 more.

To report this condition, pick the subcode that matches the documentation: C4A.51 (skin), C4A.52 (breast) and C4A.59 (trunk).

The conditions in its Excludes2 note aren't part of C4A.5, but may be coded alongside it if the patient has both: malignant neoplasm of anus NOS (C21.0) and malignant neoplasm of scrotum (C63.2).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.