What should be looked up to determine the primary site of neoplasm?

The primary site of a neoplasm refers to the original location where the cancer starts. To ascertain this, morphological characteristics of the neoplasm are essential. Morphology involves studying the structure and form of the tumor cells as they appear under a microscope. This information helps determine the type of disease and the specific location where it may have originated. Different tumors exhibit distinct morphological features that can guide the coder in identifying the site of the neoplasm.

In contrast, the diagnosis code is typically assigned based on the final determination of the disease rather than providing insight into primary site location. Clinical symptoms, while informative about the patient’s condition, do not specify where the neoplasm originated. Similarly, transformation patterns might provide information about how a tumor has changed over time or evolved but do not directly indicate the primary site of the cancer. Therefore, examining the morphology gives the most pertinent details needed to identify the primary site effectively.