Chapter 2: Neoplasms
Note:Functional activity
All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code fromChapter 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, suchas for malignant melanoma and certain neuroendocrine tumors, the morphology (histologic type) is included in thecategory 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 tothe subcategory/code .8 ('overlapping lesion'), unless the combination is specifically indexed elsewhere. For multipleneoplasms of the same site that are not contiguous, such as tumors in different quadrants of the same breast, codesfor 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 malignantneoplasms are coded to pancreas, unspecified (C25.9).