Question: The physician documents that the patient has a malignant neoplasm of her right olfactory nerve. Which ICD-10 code should we report for this condition? Wisconsin Subscriber Answer: You should report C72.21 (Malignant neoplasm of right olfactory nerve). Reporting for malignant neoplasms in the cranial nerves can be challenging because there are 12 cranial nerves. However, you don’t have a corresponding code for each nerve, nor do you have a code encompassing all of them. When the physician documents the diagnosis of neoplasm in a cranial nerve, you should read the clinical record in detail and try to find out which cranial nerve was involved. The physician may document the involved cranial nerve in either number or nomenclature. When you submit claims for malignant neoplasms in the cranial nerve(s), you can navigate to the right code by adopting the following three steps: