Rheumatoid nodules are white, fibrous submucosal nodules located on the vocal cords. They are sometimes described as “bamboo nodes,” because of the medial to lateral orientation of the submucosal lesion. Rheumatoid nodules in other areas of the body (elbows, knuckles, etc.) are almost always seen in the context of rheumatoid arthritis. In the larynx, they seem to occur with other autoimmune disorders, and sometimes as the first manifestation of an autoimmune disorder, before the patient has any other symptoms besides hoarseness.
The other entity in the differential diagnosis would be an epidermoid cyst, though distinguishing between the two is usually fairly simple on visual criteria alone. The key features for epidermoid cysts is that they are spherical rather than being oriented in a medial-to-lateral direction. If an epidermoid cyst begins to leak its contents, its shape can also become oval or oblong, but the axis of the submucosal white mass is anterior to posterior. Other distinguishing features of rheumatoid nodules are that they are routinely bilateral and sometimes even multiple as seen in some of the photo series below.