Duplicated pituitary gland and odontoid process. A case report.

The development of the pituitary gland is not well understood, but duplication of the gland, a rare embryonic anomaly, may shed some light on the process. Since 1880 only about 40 cases have been described. A 56-year-old woman complained of chronic bilateral upper extremity paresthesia and numbness along her first three fingers relieved by rest and exacerbated by increased activity. Magnetic resonance imaging of her head and neck showed an incidental discovery of a duplication of the pituitary infundibulum and pituitary fossa. Computed tomography of the neck showed congenital fusion of C2 with C3, C4 with C5, C1 with the occipital bone, and a duplication of the odontoid process. Her physical examination and all laboratory data were negative. Only seven patients with a pituitary duplication have ever survived beyond puberty. While all of these patients had normal mental capabilities, they also all had obvious craniofacial malformations. Unlike our patient, all other reported cases of duplicated pituitaries have been associated with abnormalities of the face or brain. Previously proposed theories for duplicated pituitary glands include failed twinning, teratogens, and an extreme form of the median cleft face syndrome. We feel that the cleft theory developed by Morton et al. best describes the cause of our patient's malformations. Such anomalous presentations will improve our understanding of how the pituitary gland develops and the order in which cranial structures develop to cause these cranial malformations.