ICD 10 Coding Alert

Question: A patient presents with a tumor of the sphenoid sinus. The physician biopsies the tumor and sends it to pathology. The patient returns for a follow-up consultation, where the physician explains that the pathology results are inconclusive and more testing needs to be done. What diagnosis code should I apply?

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Answer: You will not come across this sort of diagnostic coding scenario often in real-time, but it's important to know how to code it if and when the situation arises. What is initially clear is that based on the inconclusive biopsy results, you will not be coding this tumor as malignant or benign. Because of this, your window of possible diagnosis codes becomes extensively smaller.

When you look up Tumor in the ICD-10 index, the entry directs you to "see also Neoplasm, unspecified behavior, by site." You are then directed to the Table of Neoplasms, where you should first look for a neoplasm of the sinus cavity. Under sinus (accessory), you find Sphenoid, which gives you the option of coding as malignant, benign, in situ, uncertain, and of unspecified behavior.

Since you can immediately rule out the first three options, your coding choices come down to D38.5 (Neoplasm of uncertain behavior of other respiratory organs) and D49.1 (Neoplasm of unspecified behavior of respiratory system). Consider these ICD-10 coding guidelines when making a coding determination on this case. Section 1.A.9.b of the guidelines states: "Codes titled 'unspecified' are for use when the information in the medical record is insufficient to assign a more specific code."

So, unspecified behavior means that the physician is currently unable to determine the behavior of the neoplasm. Uncertain behavior, on the other hand, is actually a definitively inconclusive diagnosis. That is, the provider has concluded that the behavior of the neoplasm cannot be determined.

Based on the fact that the provider has recommended follow-up testing to determine the behavior of the neoplasm, you can confidently conclude that the neoplasm falls under the "of unspecified behavior" coding category. You will apply code D49.1 until the provider can reach a more definitive diagnosis.