A Late Diagnosis of Cushing's Disease

Introduction: Cushing’s disease is a well-known entity that is frequently described in the literature; however, amongst all pituitary lesions, ACTH-secreting tumors are among the least prevalent and are frequently diagnosed later in the disease course when compared to other functional adenomas. Here we describe a case of Cushing’s disease in a patient who had gone without a diagnosis for many years despite her vast symptomatology.

Case Description: A 60-year-old woman presented for a transsphenoidal resection of a pituitary tumor. Endocrinology was consulted for post-operative monitoring. Initially thought to be the usual case of watching for diabetes insipidus and secondary adrenal insufficiency, this patient provided an extensive and unusual history.

About 15 years prior, the patient abruptly began to gain weight notwithstanding a healthy diet and a busy lifestyle. After a year of dedicated lifestyle modifications failing to allow for weight loss, the patient underwent bariatric surgery alongside her sister (who had also gained a tremendous amount of weight attributed to overeating). The patient’s sister succeeded in losing a great deal of weight, however the patient plateaued after losing approximately 35 pounds.

During the next few years, the patient started breaking bones, first her hip, then her sternum. Her inpatient medical team checked her ACTH, which was found to be 747 pg/mL (reference range 7.2-63.3 pg/mL). They then checked her AM cortisol, which was not surprisingly elevated to 56.5 mcg/dL (reference range 6.0-18.4 mcg/dL). The patient endorsed numerous symptoms of Cushing’s disease and was referred to an endocrinologist who ordered an MRI of her brain, revealing a macroadenoma. The patient underwent tumor resection and was able to lose over 100 pounds over the course of the next year.

Over the following 10 years, the patient remained asymptomatic, until she suddenly, and familiarly, began to gain a copious amount of weight and again experienced fatigability, easy bruising, and hair growth. The patient knew to re-present to her endocrinologist, at which time both her ACTH and cortisol were both elevated (1082 pg/mL and 39.0 mcg/dL, respectively). An MRI of the brain performed at that time revealed recurrence of her pituitary tumor. The patient went for a second resection of her pituitary lesion, after which time our endocrinology team was consulted. Patient did require treatment for diabetes insipidus, secondary AI, and central hypothyroidism, however her symptoms of Cushing’s quickly resolved, and her AM cortisol two days post-operatively was found to be 0.7 mcg/dL, indicating a successful tumor removal.

Discussion: This particular case of Cushing’s disease recurrence highlights the importance of continued post-operative monitoring. Although frequent monitoring may not be indicated, and blood work and imaging may be spaced out, it may be good practice to watch these patients closely to prevent further disease sequalae. Furthermore, we are reminded that a secondary workup of obesity is of paramount importance, as this patient likely would not have required bariatric surgery has she been properly workup up for endocrinological causes of weight gain.