A series of complications after third molar osteotomy in a pancytopenia patient and spontaneous healing after bone marrow transplantation

Complications can result from the surgical removal of third molars, and the complication rate is expected to be higher in immunosuppressed patients. However, such cases are rare. Leflunomide is a slow-acting antirheumatic agent used in the treatment of rheumatoid arthritis and psoriatic arthritis. It inhibits dihydroorotate dehydrogenase, a key enzyme in pyrimidine metabolism that is particularly significant in the cell division of T lymphocytes, and suppresses leukocyte migration. In the intestinal wall and the liver, leflunomide is converted into its active metabolite, A771726, which is further metabolized into additional active substances. The half-life of these active leflunomide metabolites is between 1 and 4 weeks. Known side effects of leflunomide are itching, mucous membrane lesions, hair loss (alopecia), diarrhea, and very rarely, agranulocytosis and fatal liver necrosis. Combination therapies with leflunomide and other basic antirheumatic drugs such as methotrexate and chloroquine are more effective than monotherapy and are widely used in nonsurgical rheumatology. However, the combination of leflunomide and methotrexate is associated with the risk of severe liver damage (eg, granulomatous hepatitis) and/or lifethreatening infections. Furthermore, the risks of longterm treatment with such a combination therapy are not yet well-known. We report for the first time a case of life-threatening complications after surgical removal of the infected mandibular third molar in a patient with leflunomideinduced pancytopenia.