Hypopituitarism with invisible pituitary stalk: two case reports of males with micropenis suggesting fetal onset of hypopituitarism.

The presence of hypopituitarism and invisible pituitary stalk on a magnetic resonance image (MRI) is commonly attributed to birth trauma. Two patients with severe hypopituitarism and invisible pituitary stalk are presented. One was born by breech delivery, the other by Cesarean section. The presence of a micropenis since early infancy in these two patients suggested that their hypopituitarism might have begun during early fetal life thus effecting penile growth during the second and third triministers of gestation. These findings raise the possibility that the association of hypopituitarism and invisible pituitary stalk may have multiple etiologies including hormonal abnormalities during early fetal life.