Which ICD-O-3 behavior code indicates a malignant tumor?

Which ICD-O-3 behavior code indicates a malignant tumor?

• A. /0
• B. /2
• C. /3
• D. /1

Answer: (C)

The main idea is that ICD-O-3 behavior codes describe how a tumor behaves, specifically its invasiveness. A malignant tumor is coded with /3, signaling that it can invade surrounding tissues and has the potential to metastasize. The other behavior codes represent different levels of severity or state: /2 is in situ (non-invasive, confined to its original site), /1 is benign (not malignant), and /0 is unspecified. So /3 is the correct choice because it uniquely denotes malignancy, whereas the other codes describe noninvasive, benign, or unknown behavior.

The main idea is that ICD-O-3 behavior codes describe how a tumor behaves, specifically its invasiveness. A malignant tumor is coded with /3, signaling that it can invade surrounding tissues and has the potential to metastasize. The other behavior codes represent different levels of severity or state: /2 is in situ (non-invasive, confined to its original site), /1 is benign (not malignant), and /0 is unspecified. So /3 is the correct choice because it uniquely denotes malignancy, whereas the other codes describe noninvasive, benign, or unknown behavior.