Desmoid tumor, intrathoracic

• 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).

neoplasms of unspecified behavior (D49.-)

Categories D37-D44, and D48 classify by site neoplasms of uncertain behavior, i.e., histologic confirmation whether the neoplasm is malignant or benign cannot be made.

neurofibromatosis (nonmalignant) (Q85.0-)

• Neoplasm of uncertain behavior of connective tissue of ear
• Neoplasm of uncertain behavior of connective tissue of eyelid
• Stromal tumors of uncertain behavior of digestive system

• neoplasm of uncertain behavior of articular cartilage (D48.0)
• neoplasm of uncertain behavior of cartilage of larynx (D38.0)
• neoplasm of uncertain behavior of cartilage of nose (D38.5)
• neoplasm of uncertain behavior of connective tissue of breast (D48.6-)

Aggressive fibromatosis