General Surgery Coding Alert

Question: When the surgeon excises a skin lesion and the pathology report returns as Merkel cell carcinoma, we've always reported 173.x (Other malignant neoplasm of skin). I've heard there is a new ICD-9 code for this condition -- what is the proper code?

Georgia Subscriber

Answer: ICD-9 provides six new codes specific for Merkel cell carcinoma based on body site:

• 209.31 -- Merkel cell carcinoma of the face

• 209.32 -- ... of the scalp and neck

• 209.33 -- ... of the upper limb

• 209.34 -- ... of the lower limb

• 209.35 -- ... of the trunk

• 209.36 -- ... of other sites.

"Other" is not unspecified: ICD-9 coding convention differentiates codes for "other sites" -- which means other specified sites -- and "unspecified" -- often referred to as "not otherwise specified" (NOS) or unknown site.

Coupled with the initial ICD-9 committee recommendation for 209.75 (Merkel cell carcinoma, unknown primary site), there was some confusion about how to report Merkel cell carcinoma NOS.

Resolved: The published 2010 ICD-9 resolves the situation by adding the descriptor "Merkel cell carcinoma NOS" under the new code 209.36. The ICD-9 committee also finalized the 209.75 (Secondary Merkel cell carcinoma) to emphasize that you should not report 209.75 for a primary tumor.

Do this: If the report specifies an unlisted body site or does not specify body site, you should report Merkel cell carcinoma using 209.36.

-- Reader Questions and You Be the Coder were prepared with the assistance of Marcella Bucknam, CPC, CCS-P, CPC-H, CCS, CPC-P, COBGC, CCC, manager of compliance education for the University of Washington Physicians Compliance Program.