Hypothalamic Hypopituitarism Caused by Pituitary Stalk Dysgenesis / 대한내과학회지

ABSTRACT

Functional defects of the pituitary gland are a rare cause of pubertal delay. The pituitary stalk is an important structure that connects the hypothalamus and pituitary gland. A defect in fusion of the pituitary stalk and anterior pituitary gland will block the function of the anterior pituitary gland. A 28-year-old man was referred to our clinic with poorly developed secondary sexual characteristics. He had undeveloped facial, axillary, and pubic hair and was Tanner stage I. Laboratory tests gave random serum testosterone < 0.025 ng/mL, luteinizing hormone (LH) < 0.1 mIU/mL, follicle-stimulating hormone (FSH) 0.626 mIU/mL, thyroid-stimulating hormone (TSH) 6.85 microIU/mL, and fT4 6.96 pmol/L. Sella magnetic resonance imaging (MRI) showed no pituitary stalk enhancement. The response in the combined pituitary function test revealed multiple hormonal defects, while the TSH response to thyrotropin-releasing hormone (TRH) was exaggerated and delayed. Therefore, we concluded that pituitary stalk dysgenesis had led to hypothalamic-type panhypopituitarism.