Endogenous Cushing's Syndrome in a Patient with Systemic Lupus Erythematosus

ABSTRACT

Systemic lupus erythematosus is an autoimmune disease for which glucocorticoids are the mainstay of treatment. Cushing's syndrome is caused by glucocorticoid excess, which can be either exogenous or endogenous. Although iatrogenic Cushing's syndrome is the most common form, especially in patients undergoing glucocorticoid treatment, endogenous glucocorticoid excess should be considered because it has a different treatment strategy. We describe a 51-year old woman with a longstanding history of SLE. She was treated with steroid and cytoxan pulse therapy and plasmapheresis. Her lupus activity had been stable for 7 years with low-dose glucocorticoid treatment. She showed excessive weight gain, easy bruising, moon facies, truncal obesity, acne, and menstrual disorder. Given her history of long-term steroid therapy, iatrogenic Cushing's syndrome was considered the most likely diagnosis; however, worsening features of Cushing's syndrome with a minimal dose of glucocorticoid led us to diagnose endogenous Cushing's syndrome due to a left adrenal adenoma. The patient underwent laparoscopic left adrenalectomy. Her SLE was controlled with transient low-dose glucocorticoid treatment, and her lupus activity remained stable without glucocorticoid treatment. This is the first reported case of concomitant endogenous Cushing's syndrome in a patient with preexisting SLE in Korea. This case shows the importance of differential diagnosis including exogenous Cushing's syndrome and endogenous Cushing's syndrome in autoimmune disease patients with glucocorticoid therapy.