Dermatology Coding Alert

Question: The surgeon in our practice usually performs a biopsy of the lesion prior to doing the Mohs, either because he does not have a biopsy report or he's not sure of the type of the patient's lesion. How do I bill for this frozen section prior to Mohs?

Florida Subscriber

Answer: Mohs micrographic surgery requires a single physician to act as the surgeon and the pathologist. For the frozen section, use 88331 (Pathology consultation during surgery; first tissue block, with frozen section[s], single specimen) with modifier 59 (Distinct procedural service) to distinguish from the subsequent Mohs.

Along with it, you should report diagnostic skin biopsy (11100, Biopsy of skin, subcutaneous tissue and/or mucous membrane [including simple closure], unless otherwise listed; single lesion) --again with modifier 59 -- "if a biopsy of a suspected skin cancer is performed on the same day as Mohs surgery because there was no prior pathology confirmation of a diagnosis," according to the CPT guidelines.

Don't miss: The Mohs code already includes frozen sections after the initial biopsy.