Congenital Hypopituitarism Associated with Complex Cranio-vertebral Junction Anomalies

Background: Abnormalities of cervical spine have been described in association with pituitary anomalies in the context of malformative syndromes with midline defects. Several genes are involved in the control of pituitary gland development, differentiation and function. In particular, the presence of os odontoideum has been reported in one case of pituitary hypoplasia, associated with leg anomalies, renal dysplasia and no aberrations of the BMP4, BMP2 and PTX1 genes. In another case odontoid process was reported to be associated with pituitary gland duplication. Here we describe a 7 year-old boy with pituitary stalk interruption syndrome (PSIS) and complex malformation of cranio-vertebral junction. Presentation: This boy was admitted to our Endocrinology Unit due to a poor growth history. Auxological evaluation showed a severe growth delay (-3.4 DS) and delayed bone age (4 years according to the Greulich and Pyle method). Physical examination revealed dysmorphic signs (short neck, low implant ears, big and stumpy hands). Neurological evaluation showed intra-rotation of right foot, motor clumsiness, slight reduction of muscle strenght in the limbs, presence of clonus on the right foot. On the light of a history of neonatal hypoglycemia and bilateral cryptorchidism, diagnosis of congenital hypopituitarism was suspected. The study of pituitary function revealed a combined pituitary hormone deficiency and therefore, a substitutive therapy with rhGH, levo-thyroxine and hydrocortisone was started. The brain MRI showed a picture of PSIS, that was associated with complex cranio-vertebral junction anomalies: presence of os odontoideum, dysmorphism of epistropheum tooth apex, median cleft of anterior and posterior C1 arc, synostosis of C2 and C3 posterior arches; at the site of stenosis the cervical cord appeared to be concentrically compressed. The child underwent urgent neurosurgery with good post-operative course. Genetic evaluation for HESX1, LHX3, LHX4, PROP1, POU1F1, SOX3 and SOX2 is ongoing. Conclusion: In patients with PSIS and neurological involvement, cranio-vertebral junction anomalies should be suspected and, if present, rapidly treated, in order to avoid the progression toward a medullary compression. All patients with these anomalies should have genetic counseling in order to identify the specific gene alterations.