Neoplasms
This chapter includes all abnormal tissue growths — both benign and malignant — commonly referred to as tumors. The majority of the chapter focuses on cancers (malignant neoplasms), categorized by anatomical site such as lung, breast, colon, or brain.
Malignant neoplasms are invasive and can metastasize (spread to other organs). Codes specify primary site, secondary site (metastasis), and whether the tumor is in situ (early-stage, non-invasive). There are also codes for benign tumors, uncertain behavior tumors, and unspecified neoplasms.
Accurate coding in this chapter is critical for oncology care, insurance claims, research, and survival statistics. Many codes differentiate laterality (left vs. right), anatomical subsite, and histological type.
This chapter also includes hematologic malignancies such as leukemia and lymphoma. Because cancer care often involves long-term treatment, coding may also reflect recurrence or remission status. Overall, this chapter classifies abnormal cell growths based on behavior (benign, malignant, uncertain) and anatomical location.
Clinical & Coding Guidelines
Chapter Notes
- Functional activity
- All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter 4 may be used, to identify functional activity associated with any neoplasm.
- Morphology [Histology]
- Chapter 2 classifies neoplasms primarily by site (topography), with broad groupings for behavior, malignant, in situ, benign, etc. The Table of Neoplasms should be used to identify the correct topography code. In a few cases, such as for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in the category and codes.
- Primary malignant neoplasms overlapping site boundaries
- A primary malignant neoplasm that overlaps two or more contiguous (next to each other) sites should be classified to the subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multiple neoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codes for each site should be assigned.
- Malignant neoplasm of ectopic tissue
- Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g., ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).