Life-threatening Pneumocystis jiroveci pneumonia following treatment of severe Cushing's syndrome.

We describe two patients with a severe Cushing's syndrome due to ectopic production of ACTH. Both patients developed a life-threatening Pneumocystis jiroveci pneumonia (PCP) shortly after treatment of the hypercortisolism was started by means of inhibition of production of glucocorticoids and glucocorticoid receptor blockade. We presume that the restored immune response elicited the clinical symptoms of the opportunistic, previously subclinical Pneumocystis jiroveci infection. The immunocompromised state and the delicate glucocorticoid balance in patients with a severe Cushing's syndrome necessitate a specific diagnostic and therapeutic approach.