SUN-LB2 Undescended Testicle and Short Stature as Manifestation of Pituitary Stalk Interruption Syndrome a Report From Saudi Arabia

Background Pituitary stalk interruption syndrome (PSIS) is a congenital disease with isolated growth hormone deficiency or multiple anterior pituitary hormone deficiencies. Here, the authors report a case of PSIS from Saudi Arabia. Clinical Case A 16 year old Saudi boy presented to the endocrine clinic with short stature and undescended testis, status post bilateral orchidopexy. He was delivered by caesarean section because of breech presentation and birth asphyxia. Investigation revealed underdeveloped secondary sexual characteristics with decreased facial and pubic hair growth. The patient height was 134 cm whereas the bone age was 9 - 11 years. Pelvis examination showed a scrotum with bilateral 1 mL testes and the stretch penile length was 3 cm. The patient laboratory investigations showed hemoglobin level of 13 g/dL, serum sodium 140 mmol/L, serum potassium 4.1 mmol/L, serum chloride 102 mmol/L, calcium 9.1 mg/dL, random blood sugar 110 mg/dL and albumin 3.8 mg/dL. A pituitary hormone profile showed hypopituitarism with thyroid, and adrenal sparing. The patient free T4 was 17.3 pmol/L (9-25 pmol/L) and synacthen test revealed a morning baseline cortisol level of 6.5 µg/dL (normal = 4.3-22.4 ug/dL) with adrenocorticotrophic hormone of 9.8 pmol/L (1.1 - 13.2 pmol/L). Insulin-like growth factor 1 level 50 ng/dL (normal = 193.0 - 731.0 ug/L), follicle-stimulating hormone 0.35 µIU/mL (normal, 0.0-10.0), and leutinizing hormone 0.4 µIU/mL (normal = 1.2-7.8). The patient’s morning testosterone level showed 8 ng/dL (normal = 280-800 ng/dL) and prolactin 116 mIU/L (normal = 86 - 324 mIU/L). There were no symptom suggestive of posterior pituitary involvement like polyuria and polydipsia as urine and serum osmolality. The MRI examination showed no pituitary gland identified in the sella turcica and no clear pituitary stalk. A T1 hyperintense focus with post-contrast enhancement was identified posterior to the optic chiasma representing an ectopic posterior pituitary gland. The growth hormone and testosterone therapy were added to medical therapy of the patients and no thyroid or hydrocortisone replacement therapy was given. Conclusion: Despite the fact that this is a rare disorder, it should always be kept in the differential diagnosis of a patient presenting with short stature. Patients with this disease have an excellent opportunity to reach normal height if they present before the joining of epiphyses.