[A rare case of autoimmune polyglandular syndrome type 2 in an elderly patient].

Autoimmune polyglandular syndrome type 2 (APS-2) is a rare and complex clinical entity, whose etiology and evolution are not fully understood. We present the case of a 78-year-old male, followed and treated for Addison's disease for 45 years, in whom macrocytosis with a hemoglobin level of 11.8 g/dL was detected during a routine evaluation. The immunological vitamin B12 deficiency led to the diagnosis of Biermer's disease, while the thyroid, diabetic and liver immunological evaluations were negative. Treatment was started with periodic injections of vitamin B12 and hormone replacement therapy (glucocorticoids and mineralocorticoids) was adjusted, which produced a favorable clinical response with progressive normalization of macrocytosis and hemoglobin levels. Long-term follow-up confirmed clinical stability and effective control of the autoimmune evolution. APS-2 is defined as the coexistence of autoimmune Addison's disease with autoimmune thyroid diseases (such as Graves' disease or Hashimoto's thyroiditis) and/or type 1 diabetes mellitus, in the absence of hypoparathyroidism. Various genetic and environmental factors appear to contribute to its development, although its exact etiology remains unknown. This clinical case supports the recommendation of active screening for autoimmune disorders in patients with Addison's disease.