Prolactin-secreting tumors: what’s new?

Prolactinoma: Clinical Characteristics, Management and Outcome

Aim Prolactinoma, a prolactin (PRL) secreting functioning pituitary tumor, is the most common of all pituitary adenomas (PA) accounting for 40-60% and dopamine agonists (DA) are the cornerstone of treatment. The aim of this study was to review the clinical presentation, treatment modalities and therapeutic outcomes of patients with prolactinomas in the South Asia region. Methods This retrospective study was conducted in the Endocrinology Department of Shaukat Khanum Memorial Cancer Hospital and Research Centre from December 2011 till December 2019. Medical records were used to retrieve for patient's demographics, clinical features at diagnosis, PRL levels and size of prolactinoma on MRI at diagnosis and after start of dopamine agonists and outcome of medical management. Results A total of 107 patients were included in this study. Mean age at diagnosis was 35 (22-54) years for men and 32 (18-50) years for women and 66.4% (71) of the patients were females. Our study included 38 (35.5%) microadenoma, 50 (46.7%) macroadenoma and 19 (17.8%) giant adenomas. At presentation, the most common symptom among females was menstrual irregularity/amenorrhea seen in 73.2% of females and among males was visual disturbance (80.6%). A significant reduction in PRL levels was seen within six to 12 months of treatment. Mean PRL levels decreased from 3162.8 ng/ml to 1.52 ng/ml. A notable decrease in tumor size was seen with medical management, mean adenoma size decreased from 2.18 cm to 1.04 cm. With cabergoline (CAB) 83.3% biochemical cure was seen compared to bromocriptine (BRC) which has 60.4%. The radiological response rate in CAB and BRC groups was 65.45% and 60%, respectively. Complete resolution of adenoma was seen in 13 patients (nine were microadenoma, two macro and two giant adenomas). The prolactin level at diagnosis was positively correlated with maximum tumor diameter (r = 0.469, P = 0.001). Two patients developed cerebrospinal fluid (CSF) rhinorrhea and the defect was repaired in both patients. Median follow-up duration was 40 (12-288) months. Conclusion Clinical presentation and demographics of prolactinoma are the same in our region when compared to the rest of the world. Cabergoline is superior to bromocriptine in prolactin normalization and tumor shrinkage but still bromocriptine is being used in a significant number of patients in low-income countries as first-line due to its low cost.

Clinical characteristics and surgical outcome of prolactinoma in patients under 14 years old

Prolactinoma is one of the most common pituitary tumors, but relatively uncommon in patients under 14 years old. Surgery is the second-line treatment for prolactinoma when patients show resistance or intolerance to medical therapy. There are only a few published series of children who underwent surgery treatment. This study is performed to investigate the clinical manifestation and surgical outcome of pituitary prolactinoma in patients under 14 years old who are resistant or intolerant to medical therapy of dopamine agonist.Thirty-six cases were included in a retrospective review of patients under 14 years old operated for prolactinoma between December 1987 and December 2015. Preoperative radiological and endocrinal evaluation was performed on every patient. All patients received operation with trans-sphenoidal approach.Based on enhanced pituitary magnetic resonance imaging (MRI) taken 2 months after the surgery, total resection was achieved in 16 patients (44.4%) and subtotal resection in 20 (55.6%). Thirty-four cases (94.4%) showed remarkable decrease of prolactin (PRL) level 7 days after surgery, and 16 (44.4%) returned to normal. All patients were followed up for 2 years. Tumor regrowth or recurrence occurred in 5 patients and secondary treatment was applied, including drug treatment in 2 patients, second surgery in 2, and radiotherapy in 1.Trans-sphenoidal pituitary surgery is an effective treatment for prolactinoma in patient under 14 years old. There is no significant difference between the patients under 14 years old and adults for prolactinoma in characteristics and treatment.

Ectopic Pituitary Adenomas Presenting as Sphenoid or Clival Lesions: Case Series and Management Recommendations

Background An ectopic pituitary adenoma presenting as a clival or sphenoid mass is a rare clinical occurrence that may mislead the clinician and result in unnecessary interventions or potential medicolegal consequences. Here, we present one of the largest multi-institutional case series and review the literature with an emphasis on radiological findings and critical preoperative workup. Methods Retrospective chart review. Results Nine patients were identified with ectopic pituitary adenomas of the sphenoid or clivus. There were four females and five males. Median age was 60 years old (range, 36-73 years). The most common presenting symptom was headache (56%). Five (56%) patients presented with a mass arising from the clivus while four (44%) presented with a mass in the sphenoid. Six (67%) patients demonstrated biochemical evidence of hypersecretion on full endocrinology panel. All masses showed evidence of enhancement with gadolinium with a propensity for adjacent bone involvement. Lesions also had a predilection for growth toward the cavernous sinus, carotid artery, or sellar floor. Surgical intervention was performed in eight patients (89%). In eight patients (89%), tumors demonstrated immunoreactivity to prolactin. Conclusions Pituitary adenomas can rarely present as an isolated sphenoid or clival mass. Lesions displayed similar magnetic resonance imaging findings with an erosive growth pattern toward the sellar floor, cavernous sinus, or adjacent carotid artery. Patients with clival or parasellar lesions with comparable features should have a preoperative workup which includes prolactin level and alert the physician to consider an ectopic pituitary adenoma in the differential to prevent unnecessary surgery and potential complications.

Inhibition of SKP2 Sensitizes Bromocriptine-Induced Apoptosis in Human Prolactinoma Cells

PURPOSE

Prolactinoma (prolactin-secreting pituitary adenoma) is one of the most common estrogen-related functional pituitary tumors. As an agonist of the dopamine D2 receptor, bromocriptine is used widely to inhibit prolactinoma progression. On the other hand, it is not always effective in clinical application. Although a dopamine D2 receptor deficiency contributes to the impaired efficiency of bromocriptine therapy to some extent, it is unknown whether there some other underlying mechanisms leading to bromocriptine resistance in prolactinoma treatment. That is the main point addressed in this project.

MATERIALS AND METHODS

Human prolactinoma samples were used to analyze the S-phase kinase associated protein 2 (SKP2) expression level. Nutlin-3/adriamycin/cisplatin-treated GH3 and MMQ cells were used to analyze apoptosis in SKP2 overexpression or knockdown cells. SKP2 expression and the interaction partners of SKP2 were also detected after a bromocriptine treatment in 293T. Apoptosis was analyzed in C25 and bromocriptine-treated GH3 cells.

RESULTS

Compared to normal pituitary samples, most prolactinoma samples exhibit higher levels of SKP2 expression, which could inhibit apoptosis in a p53-dependent manner. In addition, the bromocriptine treatment prolonged the half-life of SKP2 and resulted in SKP2 overexpression to a greater extent, which in turn compromised its pro-apoptotic effect. As a result, the bromocriptine treatment combined with C25 (a SKP2 inhibitor) led to the maximal apoptosis of human prolactinoma cells.

CONCLUSION

These findings indicated that SKP2 inhibition sensitized the prolactinoma cells to bromocriptine and helped promote apoptosis. Moreover, a combined treatment of bromocriptine and C25 may contribute to the maximal apoptosis of human prolactinoma cells.

Contemporary indications for transsphenoidal pituitary surgery

OBJECTIVE

To analyze current indications for transsphenoidal pituitary surgery.

METHODS

The current literature regarding transsphenoidal surgery for all subtypes of pituitary adenomas and other sellar lesions was examined. Alternate approaches for pituitary surgery were also reviewed.

RESULTS

Transsphenoidal surgery continues to be the mainstay of surgical treatment for pituitary tumors, and has good outcomes in experienced hands. Pre- and postoperative management of pituitary tumors remains an important part of the treatment of patients with pituitary tumors.

CONCLUSIONS

Even as medical and surgical treatment for pituitary tumors evolves, transsphenoidal surgery remains a mainstay of treatment. Outcomes after transshenoidal surgery have improved over time. Neurosurgeons must be aware of the indications, risks and alternatives to transsphenoidal pituitary surgery.

Bromocriptine therapy for the treatment of invasive prolactinoma: the single institute experience

Objective

The objective of this study was to describe and characterize the clinical course of treatment for invasive prolactinoma patients using bromocriptine.

Methods

The study group included 23 patients who were treated with bromocriptine for their invasive prolactinomas. Clinical histories, serum prolactin level and pituitary hormone assessments, tumor diameter and signal intensity on sella magnetic resonance imaging (MRI), visual field exams and the dosage of medications were reviewed for each patient.

Results

During 30 months (median, range 6-99) of follow-up period, 19 patients treated with bromocriptine alone achieved biochemical remission. Four patients changed the medication to cabergoline due to the adverse effects or observed resistance of bromocriptine treatment. All of five patients who had visual symptoms improved after the course of medication. Four surgically treated patients were not able to discontinue medication because they could not maintain biochemical remission state without medication. Multivariate analysis showed that decreased enhancement on the initial followed MRI after medication and longer follow-up periods were associated with higher radiologic response.

Conclusion

We reassure that the dopamine agonist is safe and effective for the treatment of invasive pituitary adenomas. Meanwhile, surgery has a limited role on biochemical remission. Decreased enhancement on the initial follow-up MRI after medication may reflect the treatment response. Further study is required to validate the role of MRI or other factors on the actual prognosis.

Epistaxis as first clinical presentation in a child with giant prolactinoma: Case report and review of literature

Pituitary tumour have a wide way of presentation. Epistaxis due to pituitary adenoma has been rarely reported. There is no report of bleeding from nose as clinical first presentation in a child. We report the first case in literature where a child had epistaxis for eight months before deterioration of vision. He was found to be having a invasive prolactinoma with normal prolactin levels.

[Prolactinoma: from quest of pregnancy to delivery]

Prolactinoma is the most frequent hormone-secreting pituitary tumor (100 for million patients) and a major cause of both female and male reproductive function disorders. Physician, gynecologist, urologist and sexologist can face this situation during their career. As part of the fertility restoration, treatment gives very satisfactory results. With adequate management, most women are expected to achieve successful pregnancies. The natural history of these tumors during pregnancy depends on their size with a risk of a clinically relevant estimate between 5 to 30 %. Their management is complex, requiring finding balance between effects of pregnancy on tumor growth and potential risks of overtreatment on fetal development. The aim of this study is to discuss the management of prolactinoma on woman before, during and after pregnancy, and to evaluate the medical and surgical alternatives regarding the actual literature.

Prolactinomas: diagnosis and treatment

Pituitary lactotrophs secrete prolactin. This process is enhanced by estrogen and inhibited by dopamine. Prolactinomas are benign neoplasms that rarely increase in size and are classified according to size as microadenomas (<10 mm diameter) or macroadenomas (>10 mm diameter). The clinical features of prolactinomas most commonly result from prolactin's effect on the gonads and breast in women and from mass effect in men. This review details the clinical features and management of patients with prolactinomas.

Recurrence of hyperprolactinaemia following discontinuation of dopamine agonist therapy in patients with prolactinoma occurs commonly especially in macroprolactinoma

CONTEXT

The optimal duration of dopamine agonist (DA) therapy in prolactinoma is unknown. There are concerns that despite low recurrence rates in highly selected groups, high recurrence rates after DA withdrawal may occur in routine practice.

OBJECTIVE

To explore recurrence of hyperprolactinaemia and predictive factors following DA withdrawal in patients with microprolactinoma and macroprolactinoma.

DESIGN

A retrospective study on adult patients with confirmed prolactinoma attending the Oxford Endocrine Department.

PATIENTS AND MEASUREMENTS

We identified patients with macroprolactinoma (n = 15) and microprolactinoma (n = 45) treated with DA therapy for >3 years, with a trial off DA therapy. None had other treatments. Measurements included recurrence of hyperprolactinaemia following DA withdrawal, tumour size (macroprolactinomas), duration of DA therapy, prolactin levels (baseline, during DA therapy, recurrence) and time to recurrence. Data were reported as mean (range).

RESULTS

During DA therapy, prolactin levels suppressed to normal range in all patients with macroprolactinoma and microprolactinoma, and most macroprolactinomas (n = 14) had substantial tumour shrinkage. Hyperprolactinaemia recurred in 93% of macroprolactinomas (n = 14) at 8·8 months (3-36) and 64% of microprolactinomas (n = 29) at 4·8 months (3-12). Duration of DA therapy was 7·5 years (4-15) for macroprolactinomas and 4·1 years (3-10) for microprolactinomas. Prolactin levels during DA therapy were 144 mU/l (7-336) for macroprolactinomas and 278 mU/l (30-629) for microprolactinomas. For microprolactinomas, prolactin levels during DA therapy were less suppressed in those with recurrence than in those without recurrence (P < 0·05).

CONCLUSIONS

In routine practice, hyperprolactinaemia recurs early in most macroprolactinomas (93%) and microprolactinomas (64%) following DA therapy discontinuation. For most macroprolactinomas, cessation of DA cannot be recommended even after 7 years of therapy.

Caveolin-1 sensitizes rat pituitary adenoma GH3 cells to bromocriptine induced apoptosis

BACKGROUND

Prolactinoma is the most frequent pituitary tumor in humans. The dopamine D2 receptor agonist bromocriptine has been widely used clinically to treat human breast tumor and prolactinoma through inhibition of hyperprolactinemia and induction of tumor cell apoptosis, respectively, but the molecular mechanism of bromocriptine induction of pituitary tumor apoptosis remains unclear. Caveolin-1 is a membrane-anchored protein enriched on caveolae, inverted flask-shaped invaginations on plasma membranes where signal transduction molecules are concentrated. Currently, caveolin-1 is thought to be a negative regulator of cellular proliferation and an enhancer of apoptosis by blocking signal transduction between cell surface membrane receptors and intracellular signaling protein cascades. Rat pituitary adenoma GH3 cells, which express endogenous caveolin-1, exhibit increased apoptosis and shrinkage after exposure to bromocriptine. Hence, the GH3 cell line is an ideal model for studying the molecular action of bromocriptine on prolactinoma.

RESULTS

The expression of endogenous caveolin-1 in GH3 cells was elevated after bromocriptine treatment. Transiently expressed mouse recombinant caveolin-1 induced apoptosis in GH3 cells by enhancing the activity of caspase 8. Significantly, caveolin-1 induction of GH3 cell apoptosis was sensitized by the administration of bromocriptine. Phosphorylation of caveolin-1 at tyrosine 14 was enhanced after bromocriptine treatment, suggesting that bromocriptine-induced phosphorylation of caveolin-1 may contribute to sensitization of apoptosis in GH3 cells exposed to bromocriptine.

CONCLUSION

Our results reveal that caveolin-1 increases sensitivity for apoptosis induction in pituitary adenoma GH3 cells and may contribute to tumor shrinkage after clinical bromocriptine treatment.