Hypersecretion of gonadotropins by a pituitary adenoma: pituitary dynamic studies and treatment with bromocriptine in one patient

Updating the Landscape for Functioning Gonadotroph Tumors

Functioning gonadotroph adenomas (FGAs) are rare tumors, as the overwhelming majority of gonadotroph tumors are clinically silent. Literature is based on case reports and small case series. Gonadotroph tumors are poorly differentiated and produce and secrete hormones inefficiently, but in exceptional cases, they cause clinical syndromes due to hypersecretion of intact gonadotropins. The clinical spectrum of endocrine dysfunction includes an exaggerated response of ovaries characterized as ovarian hyperstimulation syndrome (OHSS) in premenopausal females and adolescent girls, testicular enlargement in males, and isosexual precocious puberty in children. Transsphenoidal surgery and removal of tumor reduces hormonal hypersecretion, improves endocrine dysfunction, and provides tissue for further analysis. Medical therapies (somatostatin analogues, dopamine agonists, GnRH agonists/antagonists) are partially or totally ineffective in many cases, especially with respect to antitumor effect. This review aims to update recent literature on these rare functioning tumors and highlight their therapeutic management.

Ovarian hyperstimulation secondary to ectopic secretion of follicle-stimulating hormone. Literature review prompted by a case

OBJECTIVE

To present an exceptional clinical case of functional follicle-stimulating gonadotropin secretion by a thorax neuroendocrine carcinoid tumor.

DESIGN

Case report.

SETTING

Department of Obstetrics and Gynecology, Cruces University Hospital, Vizcaya, Spain.

PATIENT(S)

A 26-year-old woman with ovarian hyperstimulation.

INTERVENTION(S)

Diagnosis algorithm.

MAIN OUTCOME MEASURE(S)

Successful management of ovarian hyperstimulation.

RESULT(S)

A 26-year-old woman seen with abdominal pain and swelling had bilateral multicystic ovaries. The diagnosis algorithm revealed the presence of ovarian hyperstimulation but with no due etiology. On the basis of the persistence of high levels of FSH a computed tomographic scan was taken looking for an FSH-producing neuroendocrine tumor.

CONCLUSION(S)

In idiopathic ovarian hyperstimulation secondary to supraphysiologic secretion of FSH, the presence of an FSH-producing neuroendocrine tumor should be considered. As far as we know, there are no similar cases with a confirmed diagnosis published in the literature.

Successful Long-Term Management of a Gonadotroph Adenoma with Bromocriptine

OBJECTIVE

To report the successful 10-year management of a gonadotroph macroadenoma with bromocriptine and review the management of gonadotroph adenomas with bromocriptine.

METHODS

We present a case and review the pertinent literature. The effectiveness of bromocriptine in the management of gonadotroph adenomas is evaluated.

RESULTS

A 62-year-old man was found to have a pituitary tumor after seeking medical assistance because of a 6-month history of headaches and blurred vision. He had decreased visual acuity and bitemporal field defects. Serum follicle-stimulating hormone (FSH) levels were increased, whereas serum luteinizing hormone and total testosterone levels were normal. Treatment with bromocriptine resulted in a decrease in serum FSH levels, complete resolution of his symptoms, and considerable improvement in his visual acuity and visual field defects. Treatment with only bromocriptine for 10 years resulted in maintenance of normal serum FSH levels and no recurrence of symptoms.

CONCLUSION

In the management of a gonadotroph adenoma, we recommend consideration of a therapeutic trial of bromocriptine. In cases that are refractory to this therapy, surgical treatment or external pituitary irradiation could then be used.

Glycoprotein-secreting pituitary adenomas

In the past, pituitary tumours that produce one or more of the glycoproteins (TSH, LH, FSH and alpha subunit) were thought to be rare. However, using modern immunocytochemical and molecular biology techniques, these tumours are being recognized with increasing frequency. Many of these tumours produce glycoprotein alpha and beta subunits in addition to intact glycoproteins. Hormone production is often low compared with tumour size, and serum hormone levels may not be elevated in these patients. Tumours that produce the gonadotrophins (LH or FSH) or alpha subunit account for the majority of clinically non-functioning pituitary adenomas. They do not cause a specific clinical syndrome, and usually present with symptoms of a large mass lesion and/or hypopituitarism. Optimal treatment of these tumours is often difficult. The initial approach is usually transsphenoidal surgery, followed by radiation therapy if there are symptoms due to residual tumour. Medical therapy of gonadotrophin and alpha subunit tumours may include the use of dopamine agonists or somatostatin analogues, although neither has been shown to consistently decrease tumour size. Preliminary trials with experimental GnRH antagonists suggest that these agents may be useful as adjuvant therapy of gonadotrophin tumours. Tumours that produce TSH are rare. Patients present with hyperthyroidism, which is often misdiagnosed as Graves' disease, as well as with symptoms of a pituitary mass lesion. Almost all TSH tumours secrete excess amounts of free alpha subunit. Optimal treatment of these tumours includes transsphenoidal surgery, followed by radiation therapy for residual tumour. The somatostatin analogue octreotide is effective in reducing excess TSH secretion from these tumours, and causes a reduction in tumour volume in a significant minority of patients.