Nelson Syndrome: A Case Report and Literature Review

OBJECTIVE: Nelson syndrome (NS) is a rare clinical disorder that can occur after total bilateral adrenalectomy (TBA), performed as a treatment for Cushing disease. NS is defined as the accelerated growth of an adrenocorticotropic hormone-producing pituitary adenoma. Our objective is to describe a case of NS and discuss it based on existing knowledge of this syndrome. METHODS: We describe the case of a woman diagnosed with NS at our facility in the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran and review published cases of NS. RESULTS: The patient, a 35-year-old woman with Cushing disease, had been diagnosed in 2006 at the endocrinology department in the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran. In 2007, a laparoscopic TBA was performed, and 2 years later, she presented with hyperpigmentation and adrenocorticotropic hormone levels of up to 11 846 pg/mL. NS was suspected, and as magnetic resonance imaging showed macroadenoma, transsphenoidal surgery was performed. The patient remained asymptomatic until 2012, when she presented with a right hemicranial headache, photophobia, and phonophobia. A fresh magnetic resonance imaging was performed, which documented tumor growth. She was referred to the Instituto Nacional de Neurologia y Neurocirugia, where she underwent surgery. CONCLUSION: NS develops as a complication of TBA, which is used as a treatment of Cushing disease. The main treatment is surgery and radiotherapy.