Spontaneously resolving lymphocytic hypophysitis as a cause of postpartum diabetes insipidus

A previously healthy 34-year-old woman developed diabetes insipidus 5 months after an uncomplicated pregnancy and delivery. MRI showed marked thickening of the pituitary stalk and prominence of the median eminence of the hypothalamus, with a somewhat small anterior pituitary gland. Further endocrine testing documented mild hyperprolactinemia and evidence of Hashimoto’s disease (elevated TSH and an elevated titer of antimicrosomal antibodies). The radiographic abnormalities resolved spontaneously over the next 3 months, leaving a partially empty sella turcica. The prolactin level also normalized, but diabetes insipidus persisted. Although die diagnosis was not biopsy-proven, this case has a number of features mat are typical of lymphocytic hypo-physitis (which are discussed); however, unlike the typical presentation of lymphocytic hypo-physitis (in which anterior pituitary involvement is prominent, usually as a pituitary mass with anterior pituitary hypofunction), this case is unusual in its presentation with diabetes insipidus and in die localization of radiographic abnormalities to the pituitary stalk and hypothalamus. These features expand and further define die spectrum of the clinical presentation of lymphocytic hypophysial. This patient’s course confirms the recent observations of others that die natural history of this disorder may be that of a self-limiting disease with spontaneous resolution. As a result, the risks associated with confirmation of the diagnosis by biopsy (or surgical resection of involved tissue) are unnecessary and inappropriate if the clinical presentation is consistent with lymphocytic hypophysial, and if subsequent follow-up demonstrates the anticipated radiographic normalization (as seen here and in other cases). Empty sella syndrome may represent the end stage of lymphocytic hypophysial in some patients.