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Oncology & Hematology Coding Alert

ICD-10-CM 2018 Update:

Minimize Mistakes By Learning New Malignant Mast Cell Disorder Diagnoses Now

Reflect greater detail for breast lumps, thanks to these new codes.

If you're used to applying C96.2 for mast cell neoplasms, then get ready for a big change. As of Oct. 1, 2017, you'll have expanded choices to more specifically address the patient's condition - and you need to start learning them now.

In other words: "It is important to remain in compliance with ICD-10-CM coding and quality measures," affirms Michele Midkiff, CPC-I, RCC, a coding consultant in Mountain View, California.

With roughly 750 new ICD-10-CM code additions, deletions, and revisions. Let us help you focus on the most relevant changes for your oncology practice.

Identify Mast Cell Disorders

If your oncologist treats mastocytosis and mast cell neoplasms, you've got some ICD-10-CM changes coming in the new year. These disorders are due to abnormal proliferation or reactivity of mast cells, which are mediator cells of inflammatory response associated with vascular tissue throughout the body.

The World Health Organization (WHO) characterizes mast cell disorders as hyperplasia, or conditions ranging from benign skin aliments to malignant neoplastic infiltrating conditions. Mast cell disorders can impact various organs including gastrointestinal tract, liver, lymph, and bone marrow, or can cause a systemic condition known as a myeloproliferative neoplasm.

To accommodate the WHO classification, ICD-10-CM made the following changes:

  • Revise C96.2 (Malignant mast cell neoplasm) and add:

      o C96.20 (Malignant mast cell neoplasm, unspecified)o C96.21 (Aggressive systemic mastocytosis)o C96.22 (Mast cell sarcoma)o C96.29 (Other malignant mast cell neoplasm)

  • Revise D47.0 to (Histiocytic and mast cell neoplasms of uncertain behavior), and add:

      o D47.01 (Cutaneous mastocytosis) (including listed conditions such as urticarial pigmentosa)
      o D47.02 (
Systemic mastocytosis)  (including listed conditions such as Isolated bone marrow mastocytosis)
      o Add "code also" instructions for any associated hematological non-mast cell lineage disease such as acute myeloid leukemia (C92.6-, C92.A-)

Revise Q82.2 (Congenital cutaneous mastocytosis); add conditions such as Congenital diffuse cutaneous mastocytosis; and distinguish Q82.2 from non-congenital codes.

Revise "Excludes" notes under D89.4 (Mast cell activation syndrome and related disorders)  to align with changes listed above.

Add Details to Breast Lump Diagnoses

When your oncologist examines patients with breast lumps, you'll need to have more info on the anatomic site if you want to assign the correct ICD-10-CM beginning Oct. 1.

For instance, the latest update to the code set adds new codes with fourth and fifth-digit specificity based on laterality and breast quadrant, as follows:

  • N63.0 (Unspecified lump in unspecified breast)
  • N63.10 (Unspecified lump in the right breast, unspecified quadrant)
  • N63.11 (Unspecified lump in the right breast, upper outer quadrant)
  • N63.12 (Unspecified lump in the right breast, upper inner quadrant)
  • N63.13 (Unspecified lump in the right breast, lower outer quadrant)
  • N63.14 (Unspecified lump in the right breast, lower inner quadrant)
  • N63.20 (Unspecified lump in the left breast, unspecified quadrant) and so on through N63.24 following the same pattern as N63.1-
  • N63.31 (Unspecified lump in axillary tail of the right breast)
  • N63.32 (Unspecified lump in axillary tail of the left breast)
  • N63.41 (Unspecified lump in right breast, subareolar)
  • N63.42 (Unspecified lump in left breast, subareolar).

The index also revises the entry for Breast Nodule to "Breast Nodule (see also Lump, breast) N63.0."

Shift Your Excludes2 Note

Underneath C79 (Secondary malignant neoplasm of other and unspecified sites...), you might be used to seeing the "Excludes2" note specifying you probably won't be reporting this code with "lymph node metasteses (C77.0)."

Change: ICD-10-CM deletes this Excludes2 note and instead moves it underneath C79.11 (Secondary malignant neoplasm of bladder).

Also, you'll find "indolent mastocytosis (D47.02)" instead of "indolent mastocystosis (D47.0) underneath revised code C96.2.

Investigate Full File for Yourself

We could only touch the highlights in this introduction to ICD-10-CM 2018 - there are other changes that might impact your lab. But many of the revisions are merely "editorial changes (some to correct typos), and not new codes or anything that actually changes how you report the codes," explains Melanie Witt, RN, CPC, MA, an independent coding expert based in Guadalupita, New Mexico.

Stay tuned to Oncology Coding Alert for more ICD-10-CM 2018 updates and impacts. Plus, you can access the file yourself at

You should use these codes Oct. 1, 2017 through Sept. 30, 2018. To help with the transition, General Equivalence Mappings (GEMs) will be available sometime in August 2017.