Objective: The prolactin levels alone are insufficient to distinguish between some cases of prolactinomas and stalk effect. We aimed to formally characterize the relationship between serum prolactin and prolactinoma volume, determine a cutoff for prolactin/mm that accurately distinguishes prolactinomas from stalk effect, and validate this cutoff in a cohort selected to include ambiguous prolactin values ranging from 50 to 150 ng/mL.
Methods: We used the Research Patient Data Registry and transsphenoidal surgery database in our institution to retrospectively identify adult patients with clinically nonfunctioning (NF) tumors (primary analysis, n = 279; validation cohort, n = 10) and prolactinomas (primary analysis, n = 94; validation cohort, n = 18). Solid tumor volumes were measured by Visage 7 software, and cystic foci within tumors were excluded.
Results: Prolactin levels were significantly correlated with prolactinoma volume (r = 0.801) but were not a relevant predictor of NF tumor size (r = 0.015). The prolactin/mm values did not overlap between NF tumors (median, 0.016; interquartile range, 0.009-0.028) and prolactinomas (median, 0.551; interquartile range, 0.265-0.845) (P < .0001). A cutoff of 0.065 ng/mL)/mm correctly discriminated between prolactinomas and NF tumors in all 401 patients in the primary analysis and validation cohort.
Conclusion: The prolactin/volume ratio correctly distinguished all prolactinomas from stalk effect in this study, including a validation cohort specifically chosen for potential ambiguity. To our knowledge, this study is the first formal volumetric analysis of prolactin secretion in pituitary adenomas, and our results suggest that the measurement of prolactin/mm is a valuable tool to better characterize challenging cases of primary tumoral secretion versus secondary hyperprolactinemia due to stalk effect.
Purpose: Non-functioning pituitary adenomas (NFPAs) are often associated with hyperprolactinemia, which is known as the "stalk effect". However, the relationships between hyperprolactinemia and the radiographic characteristics of the tumor that affects the pituitary stalk have not been well characterized. We aimed to identify the differences in the clinical and radiographic characteristics of patients with NFPA, with and without hyperprolactinemia.
Hyperprolactinemia can lead to issues like menstrual irregularities, infertility, and other health problems, caused by various factors categorized as physiological, pharmacological, and pathological.
It’s crucial to differentiate prolactinomas (tumors producing prolactin) from other conditions that could cause elevated prolactin levels, especially due to pituitary stalk disconnection.
The Brazilian Federation of Gynecology and Obstetrics Associations and the Brazilian Society of Endocrinology and Metabolism have outlined guidelines for measuring serum prolactin and investigating hyperprolactinemia, whether it presents symptoms or arises from medications.
Key Clinical Message: Ectopic pituitary adenoma is a rare neoplasm located in the clivus and could mimic other clival tumors. Diagnosis and treatment could be challenging. It should be considered in the differential diagnosis of clival tumors.
Objective: To evaluate the combined predictive value of MRI criteria with the prolactin-volume-ratio (PVR) to differentiate prolactinoma from non-prolactinoma, in small sellar lesions with hyperprolactinemia.
Methods: Retrospective analysis of 55 patients with sellar lesions of ≤15 mm diameter on MRI and hyperprolactinemia of ≤150 ng/mL, surgically treated between 2003 and 2020 at the Medical University of Vienna, with a conclusive histopathological report. Serum prolactin levels, extent of pituitary stalk deviation, size and volume of the lesion were assessed.
