Surgical management of thyrotropin-secreting pituitary adenomas

Gamma knife radiosurgery is effective in patients with thyrotropin-secreting pituitary adenomas

PURPOSE

Thyrotropin (TSH)-secreting pituitary adenoma (TSHoma) is a rare cause of TSH-dependent hyperthyroidism. The first therapeutic option is surgery. Medical treatment with somatostatin analogs is also effective. To obviate the need for lifelong drug therapy, gamma knife radiosurgery (GKRS) might be considered in selected patients. We report the largest series of patients with TSHoma treated by GKRS at a single center.

METHODS

This study was a retrospective analysis of 18 consecutive patients with TSHoma treated by GKRS between 1994 and 2022. Normalization of hyperthyroidism, when present at the time of surgery, and control of tumor growth were the main outcomes of the study.

RESULTS

The median follow-up after GKRS treatment was 114 months (IQR, 57-213 months; range 17-285 months). No patients had growth of the residual tumor after GKRS. Remission of hyperthyroidism occurred in 9 of the 11 (81.8%) patients who were hyperthyroid before GKRS. The probability of hyperthyroidism remission three years after GKRS was 59.1% (95% CI 27.9-90.3%). No major side effects occurred after GKRS. One patient out of the 15 patients (6.7%) with normal baseline adrenal function and follow-up longer than 3 years developed new onset hypoadrenalism, while hypogonadism did not occur in the 13 patients with baseline normal function.

CONCLUSION

Our study shows that GKRS is an effective and safe adjuvant treatment for selected patients with residual or recurring TSHoma. The option of GKRS as an alternative treatment to lifelong medical treatment with somatostatin analogs should be thoroughly discussed with the patients.

Thyrotropin-secreting pituitary adenomas: a systematic review and meta-analysis of postoperative outcomes and management

PURPOSE

TSH-secreting pituitary adenomas are rare pituitary tumors. An efficient treatment is essential to limit the mortality and morbidity in untreated patients. The aim of this study is to summarize the evidence about the postoperative outcomes and management of this rare pathology.

METHODS

A systematic search and meta-analysis of surgical series was performed.

RESULTS

Our analysis included 23 articles (536 patients). No sex difference was observed and mean age at diagnosis was 45 years. Hyperthyroidism was reportedly clinical in 67% and biochemical in 90% of patients. Co-secretion of other pituitary hormones was present in 42% of cases. Macroadenomas were found in 79% of patients, showing in 44% and 30% of cases respectively extrasellar extension and cavernous sinus invasion. The pooled rate of postoperative biochemical remission was 69.7% and a gross total resection (GTR) was observed in 54% of patients. The extent of resection was significantly increased in microadenomas (p < 0.001) and cavernous sinus invasion was predictive of lower GTR rate (p < 0.001). A biochemical remission was achieved in 66% of patients after adjuvant radiation therapy and in 76% after adjuvant medical treatment. The combination of both allowed remission in 67% of cases. At final follow-up the overall biochemical remission rate was significantly improved (85.8%) when compared to the postoperative biochemical remission (p < 0.001).

CONCLUSION

When compared to the early postoperative period, at last follow-up biochemical remission was significantly greater (p < 0.001). GTR was achieved in half of patients; the size of tumor and cavernous sinus invasion determined the extent of resection.

High Prevalence of Radiological Vertebral Fractures in Patients With TSH-Secreting Pituitary Adenoma

Background

Bone loss and high risk of fractures have been reported in patients with primary hyperthyroidism, whereas data on skeletal health in TSH-secreting adenoma (TSH-oma) are scant, and the risk of fractures in this specific clinical context has not been investigated so far. In this cross-sectional study, we aimed at evaluating for the first time, to our knowledge, the prevalence and determinants of radiological vertebral fractures (VFs) in patients with TSH-oma.

Methods

Twenty-two patients (10 males, 12 females; median age 47 years) with TSH-oma and 44 patients (20 males, 24 females; median age 49 years) with nonfunctioning pituitary adenoma (NFPA) were retrospectively evaluated for thoracic VFs using a morphometric approach on lateral chest X-ray routinely performed in the presurgical diagnostic workup.

Results

The prevalence of VFs was significantly higher in TSH-oma vs NFPA (59.1% vs 22.7%; P = 0.003), the difference being still significant (odds ratio, 10.5; P = 0.005) after correction for the size of pituitary adenomas and biochemical parameters. In TSH-oma, the prevalence of VFs was significantly associated with older age (P = 0.007) and higher serum free T4 values (P = 0.02). In 20 patients, data on presurgical medical therapies of TSH-oma were available. All patients not treated with somatostatin receptor ligands were fractured compared with 25% of those who were treated with these drugs (P = 0.001). No significant (P = 0.25) association between VFs and treatment with methimazole was found.

Conclusions

This study provides the first evidence, to our knowledge, that patients with TSH-oma may develop VFs in close relationship with severity of hyperthyroidism.

Metabolic In Vivo Visualization of Pituitary Adenomas: a Systematic Review of Imaging Modalities

OBJECTIVE

Pituitary adenomas (PAs) are the most common intrasellar mass. Functional PAs constitute most of pituitary tumors and can produce symptoms related to hormonal overproduction. Timely and accurate detection is therefore of vital importance to prevent potentially irreversible sequelae. Magnetic resonance imaging is the gold standard for detecting PAs, but is limited by poor sensitivity for microadenomas and an inability to differentiate scar tissue from tumor residual or predict treatment response. Several new modalities that detect PAs have been proposed.

METHODS

A systematic review of the PubMed database was performed for imaging studies of PAs since its inception. Data concerning study characteristics, clinical symptoms, imaging modalities, and diagnostic accuracy were collected.

RESULTS

After applying exclusion criteria, 25 studies of imaging PAs using positron emission tomography (PET), magnetic resonance spectroscopy (MRS), and single photon emission computed tomography were reviewed. PET reliably detects PAs, particularly where magnetic resonance imaging is equivocal, although its efficacy is limited by high cost and low availability. Single photon emission computed tomography possesses good sensitivity for neuroendocrine tumors but its use with PAs is poorly documented. MRS consistently detects cellular proliferation and hormonal activity, but warrants further study at higher magnetic field strength.

CONCLUSIONS

PET and MRS appear to have the strongest predictive value in detecting PAs. MRS has the advantage of low cost, but the literature is lacking in specific studies of the pituitary. Due to high recurrence rates of functional PAs and low sensitivity of existing diagnostic workups, further investigation of metabolic imaging is necessary.

Clinicopathological characteristics and therapeutic outcomes in thyrotropin-secreting pituitary adenomas: a single-center study of 90 cases

OBJECT

The aim of this study was to analyze clinicopathological characteristics and treatment outcomes in a large single-center clinical series of cases of thyrotropin (TSH)-secreting pituitary adenomas.

METHODS

The authors retrospectively reviewed clinical, pathological, and treatment characteristics of 90 consecutive cases of TSH-secreting pituitary adenomas treated with transsphenoidal surgery between December 1991 and May 2013. The patient group included 47 females and 43 males (median age 42 years, range 11-74 years).

RESULTS

Sixteen tumors (18%) were microadenomas and 74 (82%) were macroadenomas. Microadenomas were significantly more frequent in the more recent half of our case series (12 of 45 cases) (p = 0.0274). Cavernous sinus invasion was confirmed in 21 patients (23%). In 67 cases (74%), the tumors were firm elastic or hard in consistency. Acromegaly and hyperprolactinemia were observed, respectively, in 14 (16%) and 11 (12%) of the 90 cases. Euthyroidism was achieved in 40 (83%) of 48 patients and tumor shrinkage was found in 24 (55%) of 44 patients following preoperative somatostatin analog treatment. Conventional transsphenoidal surgery, extended transsphenoidal surgery, and a simultaneous combined supra- and infrasellar approach were performed in 85, 2, and 3 patients, respectively. Total removal with endocrinological remission was achieved in 76 (84%) of 90 patients, including all 16 (100%) patients with microadenomas, 60 (81%) of the 74 with macroadenomas, and 8 (38%) of the 21 with cavernous sinus invasion. None of these 76 patients experienced tumor recurrence during a median follow-up period of 2.8 years. Stratifying by Knosp grade, total removal with endocrinological remission was achieved in 34 of 36 patients with Knosp Grade 0 tumors, all 24 of those with Grade 1 tumors, 12 of the 14 with Grade 2 tumors, 6 of the 8 with Grade 3 tumors, and none of the 8 with Grade 4 tumors. Cavernous sinus invasion and tumor size were significant independent predictors of surgical outcome. Immunoreactivity for growth hormone, prolactin, or both hormones was present in 32, 9, and 24 patients, respectively. The Ki-67 labeling index was less than 3% in 71 (97%) of 73 tumors for which it was obtained and 3% or more in 2. Postsurgery pituitary dysfunction was found in 15 patients (17%) and delayed hyponatremia was seen in 9.

CONCLUSIONS

TSH-secreting adenomas, particularly those in the microadenoma stage, have increased in frequency over the past 5 years. The high surgical success rate achieved in this series is due to relatively early diagnosis and relatively small tumor size. In addition, the surgical strategies used, such as extracapsular removal of hard or solid adenomas, aggressive resction of tumors with cavernous sinus invasion, or extended transsphenoidal surgery or a simultaneous combined approach for large/giant multilobulated adenomas, also may improve remission rate with a minimal incidence of complications.

A long-term follow-up study of eighteen patients with thyrotrophin-secreting pituitary adenomas

OBJECTIVE

TSH-secreting pituitary adenomas (TSH-omas) are a rare cause of thyrotoxicosis. First-line therapy for these tumours is neurosurgery, although medical therapy with somatostatin analogues (SSAs) is increasingly used for this indication.

DESIGN AND PATIENTS

We retrospectively reviewed the data of patients with a TSH-oma (n = 18, 67% males) followed between 1989 and 2011 (median follow-up 7 years, range 1-21) in three academic medical centres in the Netherlands, focusing on the role of SSA treatment.

MEASUREMENTS

Patient records were reviewed for clinical, biochemical, imaging, pathological and treatment characteristics.

RESULTS

At initial evaluation, biochemical hyperthyroidism with non-suppressed TSH concentrations was detected in 94% of the patients. The majority of patients (72%) had a macroadenoma with extrasellar extension. Fourteen patients underwent surgery, resulting in postoperative euthyroidism in six patients (43%). Recurrence of hyperthyroidism developed in three of them after 5, 24 and 32 months, respectively. Adjuvant radiotherapy (n = 2) did not induce remission. Three patients received SSA therapy exclusively, resulting in apparent cure in one of them. During long-term follow-up, 72% of all patients required medical therapy (mostly SSA treatment). Euthyroidism was achieved in all but one patient, who refused all treatments.

CONCLUSIONS

Our results demonstrate that patients with TSH-omas, who often present with large macroadenomas with extrasellar extension, have an excellent response to SSA therapy. Because the results of surgery and radiotherapy are disappointing, primary medical therapy may be considered in virtually all patients, except in case of optic chiasm compression, especially in those harbouring large adenomas with parasellar extension.

Asymptomatic thyrotropin-secreting pituitary macroadenoma in a 13-year-old girl: successful first-line treatment with somatostatin analogs

BACKGROUND

Thyrotropin-secreting pituitary adenomas (TSHomas) are an extremely rare cause of hyperthyroidism. Up to now there are only few cases reported in the pediatric age range. Thefirst therapeutic option is surgical resection, whereas medical treatment with somatostatin analogs has been reported only in cases wherein surgery was unsuccessful.

PATIENT FINDINGS

A 13-year-old girl was referred to our clinic for incidental finding of increased circulating free thyroid hormones in the presence of detectable TSH concentrations. She had no signs/symptoms of thyrotoxicosis. Resistance to thyroid hormone was excluded due to the lack of TSH response after thyrotropin-releasing hormone (TRH) stimulation test. Cerebral magnetic resonance imaging showed the presence of a large pituitary macroadenoma, with intra- and suprasellar extension. We decided to treat this patient with somatostatin analog as a first-line therapy because of high surgery risks due to the tumor dimensions. The response to medical treatment was excellent, with rapid and significant tumor shrinkage. No major side effects were reported. The patient developed central hypothyroidism that was corrected with L-thyroxine therapy.

SUMMARY

We report the first pediatric case of TSHoma treated with somatostatin analog as a first-line therapy. The diagnosis was challenging because of the insidious and asymptomatic presentation of the tumor.

CONCLUSIONS

We conclude that somatostatin analogs should be considered as first choice, bridge-to-surgery treatment in young patients, in order to reduce neurosurgical complications and prevent hypopituitarism during pubertal development.

Thyrotropin-secreting pituitary adenoma in an adolescent boy: challenges in management

Thyrotropinomas tend to be aggressive, invasive tumors that are difficult to resect because of their marked fibrosis and their proximity to vital structures such as the optic chiasm. The latter characteristic also limits the use of radiation therapy. In the few cases reported of children younger than 18 years whose thyrotropinomas were treated surgically, the results were disappointing. We present here the case of a 16-year-old boy with a thyrotropin-secreting pituitary macroadenoma who underwent partial resection via a transsphenoidal approach and was left with significant residual tumor and continued hyperthyroidism. He subsequently received 4 years of long-acting release somatostatin therapy, during which he has remained euthyroid without requiring antithyroid medication. To our knowledge, this is thus far the longest duration of somatostatin therapy in the pediatric age group. This regimen also achieved a decrease in compression of the optic nerve and prevented further tumor growth. We review here the current literature on somatostatin analog treatment including molecular mechanisms and promising new treatment modalities, such as the heterodimerization of dopamine and somatostatin receptors. We conclude that this has been a useful adjuvant treatment for our adolescent patient.

Clinical aspects and therapeutic outcome in thyrotropin-secreting pituitary adenomas: a single center experience

BACKGROUND AND AIM

The management of pituitary adenomas secreting TSH has evolved considerably over the last decades.We report the clinical features, management, and outcome of a large monocentric series.

MATERIAL AND METHODS

A monocentric retrospective cohort of 26 patients admitted to our Department of Endocrinology between 1983 and 2007, followed for a period up to 204 months. The diagnosis of TSH-secreting adenoma was based on clinical and biochemical findings of central hyperthyroidism. Evaluation of basal and dynamic pituitary function, magnetic resonance imaging or computerized tomography scan were performed in all patients. Twenty-two patients, of whom 15 pre-treated by somatostatin analogs (SSA), underwent trans-sphenoidal surgery and were regularly re-evaluated.

RESULTS

The number of cases increased over the years. Age at diagnosis, micro- to macroadenoma ratio, and mean estimated latency between first symptoms and diagnosis did not appreciably change over time. Latency was significantly shorter in macroadenomas. Following surgery, 55% of patients obtained remission (success rate of 40 and 67% in macro- and microadenomas, respectively). SSA pre-treatment led to an apparent although not statistically- significant increase in success rate in micro- but not in macroadenomas.

CONCLUSIONS

In a monocentric group of 26 TSH-secreting adenomas the high ratio between micro- and macroadenomas remained stable over time with a significantly shorter diagnosis latency in macroadenomas. A more precocious recognition of the tumors and possibly the use of presurgical SSA allowed a high remission rate. A varied combination of neurosurgery, SSA, radiotherapy, and thyroid ablation led to the control of the disease in all the patients studied.

Coexistence of TSH-secreting pituitary adenoma and autoimmune hypothyroidism

OBJECTIVE

TSH-secreting pituitary adenomas account for about 1-2% of all pituitary adenomas. Their diagnosis may be very difficult when coexistence of other diseases masquerades the clinical and biochemical manifestations of TSH-hypersecretion.

CLINICAL PRESENTATION

A 41-yr-old female patient, weighing 56 kg, was referred for evaluation of an intra- and suprasellar mass causing menstrual irregularities. Eight yr before, the patient had been given a diagnosis of subclinical autoimmune hypothyroidism because of slightly elevated TSH levels and low-normal free T4 (FT4). Menses were normal. Despite increasing doses of levo-T4 (L-T4; up to 125 microg/day), TSH levels remained elevated and the patient developed mild symptoms of hyperthyroidism. After 7 yr, the menstrual cycle ceased. Gonadotropins were normal, whereas PRL level was elevated at 70 microg/l and magnetic resonance imaging (MRI) of the hypothalamic- pituitary region revealed a pituitary lesion with slight suprasellar extension. The tumor was surgically removed and histological examinations revealed a pituitary adenoma strongly positive for TSH. Three months after surgery the patient was well while receiving L-T4 75 microg/day and normal menses had resumed. MRI of the hypothalamic-pituitary region showed no evidence of residual tumor. At the last follow-up, 16 months after surgery, serum TSH, free T3 (FT3), and FT4 levels were normal.

CONCLUSIONS

Coexistence of autoimmune hypothyroidism and TSH-secreting pituitary adenoma may cause further delays in the diagnosis of the latter. In patients with autoimmune hypothyroidism, one should be aware of the possible presence of a TSH-secreting pituitary adenoma when TSH levels do not adequately suppress in the face of high doses of L-T4 replacement therapy and elevated serum thyroid hormone levels.