Oncology & Hematology Coding Alert

Question: What is the correct way to code a mediastinal mass? When I look up mass in the ICD-10-CM Alphabetic Index, I am led to R22.2, which describes a mass of the chest or trunk. But the R22 codes are for the skin and subcutaneous (SQ) tissue, and mediastinal masses are deeper than that. My knowledge of anatomy and physiology (A&P) tells me it may be better to use J98.59. Is that a better choice?

AAPC Forum Participant

Answer: In this situation, you will definitely need to query the physician to get more information on the composition of the mass. Assuming the mass is of tissue and not bone, you would be correct in saying that the R22.- (Localized swelling, mass and lump of skin and subcutaneous tissue) codes describe masses of the skin and SQ tissue. So, you should let the Alphabetic Index guide you to R22.2 (Localized swelling, mass and lump, trunk).

This means you would not be correct in using J98.59 (Other diseases of mediastinum, not elsewhere classified) to describe a mediastinal mass, even though it seems to run counter to your A&P knowledge.

Why? When you choose a code following ICD-10-CM guideline I.B.1, your coding will more likely be supported and withstand scrutiny. The guideline tells you that “to select a code in the classification that corresponds to a diagnosis or reason for visit documented in a medical record, first locate the term in the Alphabetic Index, and then verify the code in the Tabular List.” This is a better way to justify your code choice than relying on your A&P knowledge, which may or may not lead you to the correct code choice. By choosing R22.2, you can fall back on the guideline to provide the rationale for the choice should you be audited.

Remember, codes are simply ways to organize diagnoses into classifications. Codes are not diagnoses themselves, and diagnoses do not always align precisely with code descriptors.