Q: I am looking for information about to how to bill for a transnasal-endoscope approach in removing a skull-base tumor. I have never been comfortable with the doctors wanting to use CPT ® 61600 (resection or excision of neoplastic, vascular or infectious lesion of base of anterior cranial fossa; extradural) to bill a non-invasive procedure. I am perplexed about which CPT code(s) to report for this type of procedure.