Rheumatoid nodules are a well-characterized common extra-articular manifestation of rheumatoid arthritis. However, the occurrence of a rheumatoid nodule in the oral mucosa is extremely rare.
We present the case of a rheumatoid nodule in the lower lip, which rarely presents with variations in the clinical manifestation, that occurred in a 48-year-old female patient with rheumatoid arthritis. The nodule was totally excised under the clinical diagnosis of either a fibroma or salivary gland lesion.
On histopathologic examination, within the deep mucosa, a necrobiotic nodule surrounded by elongated histiocytic cells with a focal palisaded arrangement. The lesion was diagnosed postoperatively as a rheumatoid nodule from the histopathologic and clinical findings.
Few studies have been performed of oral rheumatoid lesions; however, a review of the published data showed that this is the first case of a rheumatoid nodule in the lower lip of a patient with rheumatoid arthritis.