BackgroundPatients diagnosed with an autoimmune disease are often systemically medicated with glucocorticoids. Autoimmune pancreatitis (AIP) Type 1 is considered a rare autoimmune disease, which is very well responsive to glucocorticoids and hence can be treated optionally on a long-term basis using low dose of the drug. Apical lesions of root canal-treated teeth can be solved by retreatment of the preexisting root canal obturation or via surgical approaches.Case presentationThis case report relates to a 76-year-old male patient, whose symptomatic acute apical periodontitis was treated nonsurgically by root canal treatment. However, overtime both roots of tooth 46 were associated with asymptomatic apical lesions. Despite progression of the lesions, due to a painless situation, the patient refrained from proceeding with any further treatment options after explaining the pathological pathway with all its consequences. A few years later the patient was prescribed 2.5 mg glucocorticoid prednisone daily for long-term therapy due to an AIP Type 1. Six years later under strict glucocorticoid therapy the apical lesions healed nearly completely and the patient remained free of symptoms without any further interventions.ConclusionsThese observations suggest that prospective clinical studies are required to further elucidate the potential healing effect of systemic long-term low-dose glucocorticoid medication on lesions of endodontic origin.