Pancytopenia and hypothyroidism: type 3B polyglandular autoimmune syndrome

Hypothyroidism can be associated with pancytopenia in rare cases. We present the case of a 33-year-old woman with edema over the past six months, associated with fatigue, hyporexia, cold intolerance, and paresthesia. Laboratory tests revealed pancytopenia and autoimmune primary hypothyroidism, along with low vitamin B12 levels associated with atrophic gastritis. Treatment with levothyroxine and prednisone was initiated for autoimmune thrombocytopenic purpura. Four weeks later, pancytopenia resolved. The final diagnosis was type 3B autoimmune polyglandular syndrome. Of the 12 reported cases of pancytopenia associated with primary hypothyroidism, a predominance in women (75%) is observed, with an average age of 55 years, and resolution with levothyroxine in an average of 47 days. Its pathophysiology involves bone marrow dysfunction due to thyroid hormone deficiency, autoimmunity, and other mechanisms. It is important to consider autoimmune hypothyroidism as a reversible cause of pancytopenia, with early hormonal treatment being essential to improve prognosis.