Revenue Cycle Insider

Question: I am still very unsure about when to use an uncertain behavior or an unspecified behavior diagnosis code. What advice can you give that will help me get this right?

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Answer: Simply stated, ICD-10-CM tells you neoplasms of uncertain behavior are neoplasms of “a specific histology type that the pathologist identifies when a neoplasm is transitioning from benign to malignant.” Neoplasms of unspecified behavior, on the other hand, are “neoplasms for which the documentation doesn’t specify the nature of the neoplasm.”

Very often, you will use an unspecified code to provide medical necessity for a biopsy, as the pathologist needs to analyze the tissue to determine nature of the tissue’s behavior. When that happens, using an unspecified code from D49.- (Neoplasms of unspecified behavior) is entirely appropriate. An unspecified behavior code would also apply when the pathologist’s documentation states the pathology is still pending or undetermined, or the provider’s documentation contains generic terms such as “mass,” “lesion,” or “tumor” without specifying the behavior.

Once the pathologist’s report comes back, however, and it explicitly states the histologic behavior of the neoplasm cannot be determined as benign or malignant, and instead the report contains language such as “dysplastic,” “atypical,” or “unusual” — and supporting documentation confirms that the cells have a specific characteristic that is not normal but not confirmed to be malignant or benign — then you will most likely assign a code from D37-D48.- (Neoplasms of uncertain behavior, polycythemia vera and myelodysplastic syndromes).

Bruce Pegg, BA, MA, CPC, CFPC, Managing Editor, AAPC