Objective: To review data on epidemiology, differential diagnosis, clinical, laboratory, and imaging findings, natural history, and management of incidentally discovered pituitary lesions (pituitary incidentalomas).
Methods: A nonsystematic review was conducted, including articles indexed in Index Medicus that contained reference to incidentally discovered pituitary masses (pituitary incidentalomas).
Results: Both autopsy and sensitive neuroimaging studies (including magnetic resonance imaging) suggest that pituitary incidentalomas are common, affecting approximately 10% of the general population. Although typically small (less than 10 mm in greatest diameter) and clinically silent, some pituitary incidentalomas may be hormonally active or cause mass effects by compressing neighboring structures. In addition, a minority of these lesions may grow over time; hence, long-term follow-up is necessary. Therapeutic interventions, including dopamine agonist therapy (in the case of prolactin-secreting adenomas) or transsphenoidal resection, are indicated in the case of pituitary lesions that are hormonally active, cause mass effects, or increase in size.
Conclusion: Pituitary incidentalomas are common and constitute a heterogeneous group with regard to pathologic features, clinical, laboratory, and imaging characteristics, natural history, and growth potential. Currently available evidence suggests that many hormonally nonfunctioning pituitary incidentalomas causing no mass effects can be safely managed by follow-up surveillance. Nonetheless, more data are needed for further elucidation of the natural history of these lesions and for improvement in accurate and noninvasive diagnosis and in prediction of growth potential of pituitary incidentalomas. Improved understanding of the pathogenesis of this heterogeneous group of lesions may also lead to the development of novel, noninvasive therapeutic agents, rationally designed to interact with well-characterized molecular targets.