Pituitary Gland Duplication and Triplication

Abstract

Duplication of the pituitary gland is a rare malformation. It can be complete, involving both the pituitary gland and stalk, or incomplete, affecting the adenohypophysis or the pituitary stalk. Exceptionally the malformation consists in a triplication of the pituitary gland and stalk. The suggested pathogenesis is duplication of the prochordal plate and rostral end of the notochord during early embryologic development. When associated with severe abnormalities, this malformation often results in death within the neonatal period. In other cases, presenting signs are delayed puberty or precocious puberty. It is commonly associated with various midline craniofacial malformations such as hypertelorism, cleft palate, tongue anomalies, choanal atresia, pharyngeal mass protruding in the oral cavity, and persistence of the craniopharyngeal canal. Intracerebral anomalies include thickening of hypothalamus caused by tubomamillary fusion, corpus callosum agenesis, thalamic fusion resulting from mass intermedia agenesis, posterior cranial fossa malformations, olfactory nerve anomalies, circle of Willis anomalies, microcephaly, neuronal migration disorders, hydrocephalus, and spinal abnormalities. Incomplete duplication is considered a less severe malformation, usually not associated with other major anomalies and allowing patients to reach adulthood. Asymptomatic forms have been reported.