Pathology/Lab Coding Alert

Question: Our pathologist examined a specimen that appeared to be submitted in fragments and is described in the operative report as excision of "bossing of the dorsal aspect of the navicular." What are the appropriate diagnosis and procedural codes to describe the condition and the examination? Kansas Subscriber Answer: The specimen you describe is a carpal boss, which is a round, bony prominence that is visible under the skin of the hand. It is an osteophyte at the base of the metacarpal and on the abutting carpal bone. These are sometimes excised because they cause chronic extensor tendon irritation when the tendon flips back and forth over the top of the boss. The appropriate diagnosis code for the condition is 726.91 (Exostosis of unspecified site). Report the pathologist's examination as 88305 (Level IV Surgical pathology, gross and microscopic examination, bone exostosis). The fact that this specimen may be submitted in fragments removed from the metacarpal and abutting carpal bone does not impact the coding. You would report this as one bone exostosis specimen, even if it is received in pieces.