Oncology & Hematology Coding Alert

Question: What is the correct code for primary central nervous system (CNS) lymphoma of the brain? I have tried searching it in the Index of the ICD-10 book, but to my surprise, I am not finding it. My coding software brings me to the C83 or the C85, but I am not sure which one is correct or if I should choose another code.>

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Answer: You are correct in saying there is no entry for lymphoma, brain in the ICD-10-CM index. There is also no entry for primary CNS lymphoma, which is the more formal name for lymphoma that starts in the brain (see www.cancer.gov/types/lymphoma/ patient/primary-cns-lymphoma-treatment-pdq).

So, a little detective work is in order to determine the most accurate code for the condition. A specified lymphoma that has no specified code would point to a code from C85.- (Other specified and unspecified types of non-Hodgkin lymphoma), and to C85.8.- (Other specified types of non-Hodgkin lymphoma) in particular. From there, you would eliminate all other codes in the group as their anatomic descriptors do not match the location of primary CNS lymphoma in the brain. That would leave you with C85.89 (Other specified types of non-Hodgkin lymphoma, extranodal and solid organ sites) as the best fit for a code to describe primary CNS lymphoma.