Mouth Ulcers in Liver Transplant Recipients as an Adverse Reaction to Tacrolimus Used in Immunosuppressive Therapy: A Report of 2 Cases

BACKGROUND Organ transplant patients take immunosuppressants to prevent transplant rejection. These substances, including cyclosporine, tacrolimus (TAC), sirolimus, and mycophenolate mofetil (MMF), can cause a variety of adverse reactions such as systemic infections, neoplastic lesions, and agranulocytosis, while the oral cavity can present with aphthous ulcers, leucoplakia, glossitis, erosions and ulcers, exophytic lesions in the oral mucosa, gingival hypertrophy, and mucosal hyperplasia. The most commonly used immunosuppressant in liver transplant (LTx) recipients is tacrolimus (TAC). Improvements in surgical techniques and the use of modern immunosuppressants have increased the long-term survival of transplant recipients, but they are still at high risk of oral lesions. CASE REPORT In the 2 liver transplant recipient patients described in this article, TAC caused necrotic and ulcerative lesions in the oral mucosa. Both patients presented similar lesions. After exclusion of other etiological factors of the lesions and the modification of immunosuppressive therapy, the lesions healed in 3-4 weeks. CONCLUSIONS Tacrolimus-induced necrotic oral ulcers are a rare adverse reaction and should be considered in the differential diagnosis for organ transplant patients with mucositis who are receiving tacrolimus therapy. Lesions of this nature occurred in both patients reported. After tacrolimus was discontinued, there was complete healing of the lesions in 3-4 weeks. Therefore, modification of the immunosuppressants used should be considered once other possible etiological factors for the lesions have been excluded. The lesions should be differentiated from mucosal injuries, blistering skin diseases, autoimmune and proliferative diseases, and hematological abnormalities. The mechanism for the development of ulcer-like lesions in the oral mucosa during therapy with tacrolimus is not known.