8129 A Case of Pituitary Stalk Interruption Syndrome Presenting With Panhypopituitarism

Abstract Disclosure: A. Salvat: None. M. Sevilla: None. Background: Pituitary stalk interruption syndrome (PSIS) is a rare congenital abnormality characterized by the classic triad of a thinned or interrupted pituitary stalk, an ectopic or absent neurohypophysis, and a hypoplastic or absent anterior pituitary gland. Clinical manifestations vary and can include neonatal hypoglycemia, short stature, cryptorchidism, and delayed puberty. Symptoms can present at birth or later in life with variable degrees of hormone deficiency. Clinical case: A 25-year-old male with hypothyroidism (on levothyroxine since age 13) presented for evaluation of hypogonadotropic hypogonadism. At birth, he was diagnosed with bilateral cryptorchidism and had frequent hypoglycemic episodes. During his childhood and early teenage years, his growth paralleled of his peers. However, at age 18, he experienced a growth spurt with unusually long arms and legs. He never developed secondary sexual characteristics. Physical examination showed blood pressure of 109/62 mmHg, height 193 cm, weight 76 kg, Tanner stage 1 pubic hair, microphallus, and nonpalpable testicles. The initial labs were consistent with panhypopituitarism: FSH 0.14 mIU/mL (0.95–11.95 mIU/mL), luteinizing hormone <0.09 mIU/mL (0.57–12.07 mIU/mL), total testosterone <4 ng/dL (240–871 ng/dL), prolactin 30.31 ng/dL (3.46–19.40 ng/dL), AM cortisol <1 ug/dL (3.7–19.4 ug/dL), ACTH 14 pg/mL (6–50 pg/mL ), cortisol levels 60 minutes after consyntropin stimulation test of 3.6 ug/dL (3.7–19.4 ug/dL), IFG-1 <16 ng/mL (63–373 ng/mL), TSH 7.24 uIU/mL (0.35–4.94 uIU/mL), free T4 0.53 ng/dL (0.70–1.48 ng/dL). Karyotype 46, XY, inv (9) (p12q13). The whole exome sequencing testing was negative. Pituitary magnetic resonance imaging showed hypoplasia of the anterior pituitary gland, ectopic location of the posterior pituitary gland at the expected base of the pituitary infundibulum anterior to the mammary bodies, and hypoplastic or absent pituitary infundibulum, findings suggestive of pituitary stalk interruption syndrome. Scrotal ultrasound showed no testicular or epididymal tissue within the scrotum. DEXA scan showed osteoporosis associated with a long history of non-treated testosterone deficiency. The levothyroxine was adjusted, and the patient was started on intramuscular testosterone, calcium, and vitamin D to manage the hypogonadism and improve the bone mineral density. Conclusion: Diagnosis of PSIS is often delayed due to its variable presentation and age of onset. Although this condition is considered rare, it should be in the differential diagnosis of patients presenting with panhypopituitarism. Early identification of deficient hormones, as well as prompt initialization of hormone replacement therapy, is essential to prevent serious complications associated with these deficiencies, such as adrenal crisis, osteoporosis, diminished quality of life, delayed puberty, and infertility. Presentation: 6/3/2024