Acute myeloid leukemia in a patient with Graves' disease, causality or coexistence?: case report

Leucemia mieloide aguda en paciente con enfermedad de Graves ¿causalidad o coexistencia?: reporte de caso

Introduction: Thyroid hormones play a regulatory role in hematopoiesis, which has led to hypotheses regarding a potential association between thyroid disease and hematologic malignancies. To date, this relationship has not been firmly established due to the lack of robust supporting evidence. This case report documents the rare coexistence of Graves’ disease and acute myeloid leukemia (AML), underscoring the importance of a comprehensive diagnostic approach in patients with persistent hematologic abnormalities. Clinical case: A 33-year-old woman with a history of Graves’ disease, previously treated with methimazole for three years, discontinued therapy for one year and resumed treatment one month prior to presenting to the emergency department. She was admitted with fever and odynophagia unresponsive to outpatient antibiotic therapy. On examination, she exhibited altered vital signs and enlarged tonsils with purulent exudate. Laboratory findings revealed bicytopenia with agranulocytosis and microcytic hypochromic anemia. Methimazole-induced agranulocytosis was suspected, leading to discontinuation of the thionamide and initiation of antimicrobial therapy and beta-blockers. Despite drug withdrawal, neutrophil counts failed to improve significantly, prompting hematology consultation. A bone marrow biopsy revealed 23.6% myeloid blasts, confirming the diagnosis of AML. This finding raises the possibility that the agranulocytosis may have been an initial manifestation of AML rather than solely a drug-induced adverse event.
Conclusion: This case highlights the need for prospective studies to explore the relationship between autoimmune thyroid disease and leukemia in order to enhance understanding and clinical management of these complex interactions.