Oncology & Hematology Coding Alert

ICD-10-CM leaves questions about MM remission, personal history, relapse, and metastasis unanswered.

Last month, we looked at how to code multiple myeloma (MM), smoldering multiple myeloma (SMM), and monoclonal gammopathy of undetermined significance (MGUS) despite insufficient ICD-10-CM guidance regarding how to assign codes for the conditions.

This month, we examine other anomalies in MM diagnosis coding guidance, such as when can you code MM as personal history rather than in remission, when you can code MM as having relapsed, and whether it is possible to code metastatic MM.

Read on to get answers you need for the most accurate MM diagnosis coding.

First, What Do the Guidelines Say About Remission and Personal History?

ICD-10-CM Official Guidelines, Section I.C.2.n., offers guidance for coding remission status for both leukemia and MM but only addresses personal history status for leukemia. It states:

“The categories for leukemia, and category C90, Multiple myeloma and malignant plasma cell neoplasms, have codes indicating whether or not the leukemia has achieved remission. There are also codes Z85.6, Personal history of leukemia, and Z85.79, Personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues. If the documentation is unclear as to whether the leukemia has achieved remission, the provider should be queried.”

However, the guideline does not clearly explain when you should code MM as a personal history other than telling coders to query the physician. The guideline also does not provide a distinction between personal history and multiple myeloma in relapse.

What Is the Difference Between MM in Remission and Personal History?

The National Cancer Institute defines remission as a “decrease in or disappearance of signs and symptoms of cancer.” Complete remission does not necessarily mean the patient is cured, and no evidence of disease means that the disease is not detected at the time of assessment. For coding purposes, however, you shouldn’t convert either phrase to “personal history.”

For MM, remission can be either partial or complete. As there is no code in ICD-10-CM for partial remission, you should assign C90.01 (Multiple myeloma in remission) when the provider documents that the disease is in remission or in partial remission.

Example: A patient is seen in the office to follow up on their MM and has no current symptoms. They completed chemotherapy six months ago. 

• Assessment: Provider documents “Multiple Myeloma, in partial remission”
• Code assigned: C90.01

However, there is no code for a personal history of MM. Although Z85.79 (Personal history of other malignant neoplasms of lymphoid, hematopoietic and related tissues) is available for conditions classifiable to C88.- (Malignant immunoproliferative diseases and certain other B-cell lymphomas) through C90.- (Multiple myeloma and malignant plasma cell neoplasms) and C96.- (Other and unspecified malignant neoplasms of lymphoid, hematopoietic and related tissue) per the instructions accompanying the code, its use for multiple myeloma warrants scrutiny.

That’s because the National Cancer Institute describes MM as not currently curable, going on to note that “it can be managed like a chronic disease in some people.” This means the condition does not satisfy the definition of personal history found in ICD-10-CM Guideline I.C.2.d. The guidance tells you “when a primary malignancy has been previously excised or eradicated from its site, there is no further treatment (of the malignancy) directed to that site, and there is no evidence of any existing primary malignancy at that site, a code from category Z85, Personal history of malignant neoplasm, should be used to indicate the former site of the malignancy.”

Clinically speaking, documentation of remission, complete remission, no evidence of disease (NED), or absence of symptoms does not, by itself, establish that MM has become a past condition.

When Should I Code Multiple Myeloma in Relapse?

The problem with assigning C90.02 (Multiple myeloma in relapse) when the patient’s MM is in relapse lies in correctly interpreting the language in the clinical documentation. For example, the provider may use the International Myeloma Foundation’s term “progressive disease" or PD. Additionally, the provider may use the term “refractory myeloma” to refer to a relapse in patients “who have had progressive disease either during treatment or within 60 days following treatment,” per the International Myeloma Foundation.

So, unless the provider clearly documents MM in relapse, be sure to clarify your provider’s terminology before using C90.02.

Understand Myeloma and Metastasis

MM is a systemic plasma-cell cancer that does not metastasize in the same way as solid tumors, which can also present a problem in coding the condition. Regardless of the number of bone sites involved, the spread of MM lesions in the bones is not considered a secondary malignant neoplasm of the bone sites and is not coded as secondary cancer. ICD-10-CM does not classify any other codes for metastasis, which is why you won’t find any mention of secondary or metastatic MM in the ICD-10-CM Alphabetic Index.

So, what happens when you encounter documentation such as the following?:

HPI: A 70-year-old patient presents to urgent care with complaints of lower back pain. The patient does not have a history of cancer.

Findings: An MRI of lumbar spine reveals widespread lytic lesions in the lumbar spine consistent with metastatic myeloma.

Assessment: The patient has metastatic MM in the lumbar spine.

In this situation, the physician has diagnosed MM and has not documented that it is in remission or relapse. The lytic lesions in the lumbar vertebrae reflect spread in the lumbar spine, and bone involvement is integral to the disease process. This differs from a solid cancer, such as breast or lung cancer, which metastasizes to the bone.

Consequently, you’ll assign C90.00 (Multiple myeloma not having achieved remission). When MM spreads within one bone or to multiple bones, code MM with the appropriate MM C90.0- code; do not add a secondary bone malignancy code for the spread of the lesions. 

Key Takeaways   

• Assign C90.01 when the provider documents “multiple myeloma in remission” and C90.02 when the provider documents “in relapse.” Do not infer disease status from test results or treatment changes alone.
• Use of terms such as remission, complete remission, NED, completed treatment, or absence of symptoms do not, by themselves, justify assigning Z85.79. Despite advances in treatment, MM is considered incurable.
• If the record shows MM as a “history of" condition but its status is unclear or conflicts with other documentation, query the provider rather than guessing.
• Similarly, the multiplicity of terms that a provider can use for MM in relapse will require you to query the provider before assigning C90.02.
• If the record states the MM is metatstic, or that a specific condition is secondary to MM, document an active MM code such as C90.00.

Delly E. Parham, CPC, CRC, CPMA, , Risk Adjustment Auditor and Coder