History A 13-year, 10-month-old boy presented with a low energy level, depression, and intermittent diarrhea. According to his growth chart, at age 7 years he was in the 25-50 percentile for height. At the time of presentation, he had fallen to the fifth percentile. Results of a bone age study indicated that his bone age, according to the standards of Gruelich and Pyle, was within 2 months of his chronologic age. Laboratory studies revealed the levels of free thyroxine and thyroid-stimulating hormone to be 12.6 pmol/L (normal range, 10.3-21.9 pmol/L) and 7.08 mIU/L (normal range, 0.36-5.4 uIU/mL), respectively. He began taking 50 mcg of Levothyroxine, which had a positive effect on his energy level. Results of physical examination at this time were remarkable for gynecomastia; the patient was referred for an endocrine evaluation. A month and a half later, the patient presented to the emergency department with shortness of breath and tachycardia. In addition, he experienced vomiting and diarrhea without fever over the previous 2 days. The patient's level of estrone was elevated at 777 pmol/L (normal range, 55.5-925 pmol/L), with estradiol at 8.1 pmol/L (normal range, 1.84-5.9), androstenedione at 2.2 nmol/L (normal range, 1.1-2.3), cortisol at 402.8 nmol/L (normal range, 140-690), and alpha-fetoprotein at 2.8 mu g/mL. Chest and abdominal computed tomography (CT) was ordered for a suspected pulmonary embolus and for liver abnormalities.