Introduction: Primary lactotroph disinhibition (stalk effect) occurs as a result of mechanical compression of the pituitary stalk. The ensuing hyperprolactinemia can result in galactorrhea, sexual dysfunction, infertility, and, in premenopausal females, amenorrhea. The time course and durability of resolution of pituitary stalk effect-related hyperprolactinemia has not yet been studied in a large cohort of patients. We performed a retrospective review to investigate the time course of recovery of lactotroph disinhibition after transsphenoidal surgery.
Methods: Medical records from Brigham and Women’s Hospital were retrospectively reviewed for all patients undergoing transsphenoidal surgery from April 2008 to November 2014. Patients with known prolactin-positive pituitary adenomas, prior surgery, or incomplete serum prolactin evaluation were eliminated from final analysis.
Results: Of 556 pituitary adenomas, 289 (52.0%) were eliminated for the following reasons: 77 (13.9%) had an immunohistochemically confirmed prolactinoma or prolactin-staining pituitary adenoma, 119 (21.4%) patients had prior surgery at an outside hospital, 93 (16.7%) had incomplete medical records/serum prolactin levels, leaving 267 (48.0%) patients for final analysis. Of these, 72 (27.0%) had elevated serum prolactin levels (=23.3ng/mL). Patients with stalk effect were more likely to present with menstrual dysfunction (p<0.01), hirsutism (p<0.01) and galactorrhea (p<0.01). Larger sellar lesions were associated with increased incidence of lactrotroph disinhibition (2.3cm+/-0.94 versus 1.91cm+/-0.99, p<0.01). Among patients presenting with stalk effect, 87.8% of patients experienced normalization of their serum prolactin, galactorrhea improved in 100% of patients, sexual dysfunction (including infertility and poor libido) resolved in 66.6%, and menstrual dysfunction among pre-menopausal females normalized in 73.3% at last follow-up (LFU).
Conclusions: Transsphenoidal surgery can provide durable normalization of serum prolactin levels and related symptoms due to pituitary stalk compression related lactotroph disinhibition.
Patient Care: Hyperprlactinemia frequently arises in patients harboring pituitary adenomas as a result of mass effect on the pituitary stalk. The effects of lactotroph dysinhibition are frequently uncomfortable and embarrassing for patients, and can be rectified surgically. Here we present data that demonstrates resolution of prolactin stalk effect secondary to surgical resection, and assess the time course of symptom resolution.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Develop an understanding of the physiologic mechanisms behind prolactin stalk effect.
2) Appreciate the typical time course for resolution of stalk effect after transsphenoidal surgery.