Prolactin-secreting Pituitary Macro-adenoma Presenting with Mass Effects, Hormonal Deficiencies, and Neurogenic Diabetes Insipidus: A Case Report and Review of Literature

To report and review a case of prolactin-producing pituitary tumor presenting with mass effects, hormonal deficiency, and neurogenic diabetes insipidus in a nulliparous woman of Afro-Caribbean descent. The patient presented with dull-aching headaches associated with worsening vision, nausea, and vomiting. The patient also complained of polyuria, nocturia, thirst, polydipsia, and weight gain. Physical examination showed bilateral visual field defects, while investigations revealed hypernatremia and elevated plasma osmolality but decreased urine sodium concentration, osmolality, and specific gravity.

Results of the hormonal profile showed high plasma prolactin levels, a low plasma concentration of the antidiuretic hormone, and decreased levels of other anterior pituitary hormones. Imaging revealed a large, uncalcified, cystic pituitary mass extending into adjacent structures and compressing the optic chiasm and internal carotid artery. The outcome of the water deprivation and desmopressin administration tests were consistent with neurogenic diabetes insipidus, and a diagnosis of prolactin-producing pituitary macroadenoma with mass effects, hormonal deficiencies, and neurogenic diabetes insipidus was made. The patient was commenced on medical treatment and referred for histopathological diagnosis and definitive treatment. This report highlights the coexistence of neurogenic diabetes insipidus with a prolactin-producing pituitary macroadenoma presenting with mass effects.