Pituitary Stalk Interruption Syndrome in a 40-Year-Old Female With Absent Uterus and Ovaries

Background: A patient with multiple pituitary hormone deficiencies due to a rare congenital pituitary defect also presented with an absent uterus and ovaries. Coexisting Müllerian agenesis was suspected, however hormone replacement unraveled a different story. Case Presentation: A 40-year-old female presented with generalized body weakness and euvolemic hyponatremia. She also had cold intolerance, constipation, primary amenorrhea and dyspareunia. As a child, she was worked up for short stature but was lost to follow up. Physical examination showed Tanner stage 1 breast and pubic hair, and absence of axillary hair. She had no facial anomalies, visual abnormalities or anosmia. Hormone panel was consistent with panhypopituitarism: ACTH 5.69 pg/mL (<46 pg/mL), cortisol 1.9 ug/dL (4.30-22.40 μg/dL), TSH 3.375 uIU/mL (0.55-4.78 uIU/mL), FT4 0.51 ng/dL (0.55-4.78 uIU/mL), FT3 1.79 pg/mL (2.30-4.20 pg/mL), LH <0.07 mIU/mL (1.9-12.5 mIU/mL), FSH 0.95 mIU/mL (2.5-10.2 mIU/mL) and IGF-1 40.8 ng/dL (109-284 ng/mL). Bone age was delayed (16-year-old) but with most ossification centers fused. Pituitary MRI showed hypoplastic anterior pituitary, ectopic posterior pituitary and absent pituitary stalk suggestive of Pituitary Stalk Interruption Syndrome (PSIS). Low estradiol 19.35 pg/mL (19.5-144.2 pg/mL) in the setting of low LH and FSH was compatible with hypogonadotrophic hypogonadism. She had female-range serum testosterone level <0.007 ng/mL (0.1209-0.5946 ng/mL) and karyotype of 46XX. Transvaginal ultrasound revealed a blind vaginal pouch with absent uterus, fallopian tubes and ovaries; hence Müllerian agenesis was also considered. Hormonal replacement with prednisone, levothyroxine and conjugated equine estrogen was started. Secondary osteoporosis was treated with alendronate, calcium and vitamin D on top of estrogen therapy. Six months after initiation of estrogen, there was appearance of a small anteverted uterus and atrophic right ovary. Müllerian agenesis was ruled out and hypogonadotropic hypogonadism was proved to be the cause of the initial absence of the uterus and ovaries on imaging. Conclusion: Increased awareness of PSIS is important since early and accurate diagnosis is crucial for timely initiation of hormone replacement. This case also demonstrates the need for reassessment after hormonal replacement in patients with severe estrogen deficiency and apparent Müllerian agenesis.