A 60-year-old woman is brought to the emergency department following a motor vehicle accident. She hit a car from her side and claims that she did not see another car coming towards her. This accident took place at a small intersection with little traffic. Her past medical history is significant for Cushing's disease and an intra-abdominal operation 15 years ago for the disease. Physical examination showed a tanned female with normal vital signs. She has a few abrasions on her face and chest. Ophthalmologic examination reveals bitemporal hemianopsia. Her injuries are managed appropriately.
What is the most likely diagnosis?

Question

A 60-year-old woman is brought to the emergency department following a motor vehicle accident.  She hit a car from her side and claims that she did not see another car coming towards her.  This accident took place at a small intersection with little traffic.  Her past medical history is significant for Cushing's disease and an intra-abdominal operation 15 years ago for the disease.  Physical examination showed a tanned female with normal vital signs.  She has a few abrasions on her face and chest.  Ophthalmologic examination reveals bitemporal hemianopsia.  Her injuries are managed appropriately.
What is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: Pituitary enlargement and hyperpigmentation following bilateral adrenalectomy for Cushing's disease is termed as Nelson's syndrome. The cause of pituitary enlargement is the loss of feedback by the adrenal glucocorticoids following bilateral adrenalectomy. The tumor in Nelson's syndrome is aggressive and is treated by surgery and/or pituitary radiation. Following bilateral adrenalectomy, prophylactic pituitary radiation sometimes prevents the development of Nelson's syndrome; however, this leads to an increased risk for hypopituitarism. Previously, bilateral adrenalectomy was the preferred treatment for Cushing's disease; however, with the advent of better localization and improved techniques of transsphenoidal surgery, primary pituitary surgery is now the preferred treatment for Cushing's disease. (Choice A)Prolactinoma can cause bitemporal hemianopsia but will not lead to increased pigmentation. Furthermore, the past history of bilateral adrenalectomy favors the diagnosis of Nelson's syndrome. (Choice C)Although craniopharyngioma can occur in adults, it is uncommon at this age. The clinical features of craniopharyngioma are visual field defects and hypopituitarism. Diabetes insipidus is more common compared to pituitary macroadenoma. (Choice D)Except for parasellar or intrasellar meningiomas, brain tumors usually do not present with bitemporal hemianopsia. Hyperpigmentation does not occur in brain tumors. (Choice E)Visual field defects are uncommon in patients with empty sella syndrome. Educational Objective: Nelson's syndrome is characterized by pituitary enlargement, hyperpigmentation, and visual field defect following bilateral adrenalectomy. Usually, these tumors are rapidly growing and can be treated with surgery and/or local radiation.

A 60-Year-Old Woman Is Brought to the Emergency Department Following