MRI findings of an incidental ectopic posterior pituitary gland in an adult: Case report and review of T1 hyperintense lesions in the literature

The ectopic posterior pituitary represents a rare congenital malformation attributable to aberrant embryogenesis of the neurohypophysis. Although it may occur as an isolated anomaly, it is frequently concomitant with other congenital malformations of the central nervous system. Despite extensive investigations, the precise etiology remains elusive; however, accumulating evidence suggests that its pathogenesis may parallel that of septo-optic dysplasia, thereby implicating a genetic predisposition. Earlier accounts predominantly attributed this anomaly to traumatic mechanisms. In contrast, contemporary studies increasingly support a hereditary basis. In this report, we delineate the magnetic resonance imaging (MRI) characteristics of an isolated ectopic posterior pituitary, incidentally discovered during an ataxia work-up in a 72-year-old female patient. Notably, the patient exhibited no clinical evidence of growth hormone deficiency or hyperprolactinemia.