Incidental Versus Symptomatic Nonfunctioning Pituitary Adenomas: Are They Different?

Background: Nonfunctioning pituitary adenomas (NFPAs) constitute one of the most common tumours in the sellar region and are often discovered only when associated with compressive symptoms. With the frequent use of brain imaging, there has been an increase in the prevalence of incidentally discovered NFPAs.

Aim: We aim to determine the prevalence of incidental diagnosis with NPAs observed over a decade and compare the analytical, clinical and treatment differences between those who were diagnosed either incidentally or symptomatically. We also intend to evaluate the pathology differences between both groups.

Methods: We retrospectively analysed patients aged ≥18 years with an apparent NFPA, defined as a pituitary lesion compatible with pituitary adenoma which is not associated with the clinical or biochemical evidence of a hormone-secreting tumour. Inclusion criteria included normal prolactin level for lesions <9 mm or a prolactin level <100 ng/mL for lesions ≥10 mm in maximal tumour diameter.

Results: We included 119 patients [53.8% males; mean age: 56.8 years (SD = 16.7)]. Diagnosis was incidental in 47.1% of patients, and many patients had unappreciated signs and symptoms of pituitary disease. In the symptomatic and incidental groups, 66.7% and 41.1% of patients had hypopituitarism, respectively (p = .005). Only 20.4% of patients incidentally diagnosed had microadenoma (p = .060). Hypopituitarism was present in 18.8% of those patients with microadenomas. Most tumours were macroadenomas (87.4%). Half of those patients diagnosed incidentally were submitted to surgery, compared with 75.8% of those who were diagnosed symptomatically (p = .004).

Conclusions: Nonfunctioning pituitary adenomas are commonly diagnosed incidentally, with many manifesting symptoms on examination. NFPAs incidentally diagnosed are more commonly macroadenomas and less frequently associated with hypopituitarism than symptomatic. Accordingly, if there was a greater level of knowledge and more suspicion about these pathologies, it might be possible to discover them earlier.