Etiologic aspects and management of acromegaly

Association of an empty sella and grave´s disease in a patient with acromegaly: a case report

Acromegaly is, in most cases, caused by growth hormone secreting pituitary adenomas. Those patients often develop different pathologies of the thyroid gland, however, the occurrence of Grave´s disease is quite a rare situation. We report a case of a 64-year-old female patient who presented with signs of hyperthyroidism and imbalance of her diabetes mellitus. On physical examination, she had facial features of acromegaly. Biochemical testing confirmed the suspicion of acromegaly and Grave´s disease, with an elevated insulin-like growth factor-1 and a suppressed thyroid stimulation hormone (TSH) with positive TSH-receptor antibodies. A pituitary Magnetic Resonance Imaging (MRI) was performed, revealing a macro-adenoma and an empty sella. The patient successfully underwent a transsphenoidal surgery and obtained a remission of her hyperthyroidism under anti-thyroid drugs.

Relationship of apelin, procalcitonin, and fetuin-A concentrations with carotid intima-media thickness in acromegaly

Background

Acromegaly is characterized by excess growth hormone and insulin-like growth factor-1 concentrations. There is conflicting evidence as to whether acromegaly is associated with an increased risk of atherosclerosis. Apelin is an adipose tissue-derived peptide that may be associated with hyperinsulinemia. Fetuin-A is a hepatocyte produced plasma glycoprotein that has an important role as a calcification inhibitor. The aim of this study was to examine apelin, fetuin-A, and procalcitonin concentrations and to assess their relationship with carotid intima medial thickness (cIMT) in subjects with acromegaly.

Methods

Apelin, fetuin-A, and procalcitonin serum concentrations were measured in 37 (20 inactive and 17 active) subjects with acromegaly and 30 control subjects, along with carotid intima medial thickness.

Results

The concentrations of apelin, fetuin-A, and procalcitonin were increased in subjects with acromegaly. There were significant correlations between apelin, fetuin-A, and procalcitonin in subjects with acromegaly. Carotid intima medial thickness values were similar between control subjects and subjects with acromegaly.

Conclusions

Carotid intima medial thickness was not increased in subjects with acromegaly. It is possible that the increased apelin and fetuin-A concentrations observed play a protective role against the development of atherosclerosis in subjects with acromegaly.

Prostatic disorders in acromegalic patients experience of a Brazilian center

INTRODUCTION

Published data suggest that patients with acromegaly have an increased prevalence of prostate disorders.

OBJECTIVE

To evaluate prostatic disorders in acromegalic patients comparing these results after one year of treatment of acromegaly and with a group of healthy men.

MATERIALS AND METHODS

This study was composed of two parts: sectional study comparing patients with healthy controls (baseline) and prospective, longitudinal study (at baseline and after one year of treatment). Forty acromegalic patients were enrolled and evaluated at baseline and after one year with the application of international prostatic symptoms score (IPSS), digital rectal examination, measurements of growth hormone (GH), insulin-like growth factor-I (IGF-I), insulin-like growth factor-binding protein-3 (IGFBP-3), sex hormone-binding globulin (SHBG), prolactin, luteinizing hormone (LH), follicle-stimulating hormone (FSH), total testosterone, total and free prostate-specific antigen (PSA) levels and prostate ultrasonography (US). Thirty healthy men were selected as control group.

RESULTS

We stratified patients and controls according to age, considering 40 years-old as cut off. Healthy controls under 40 had IPSS values lower than acromegalic patients. When considering only older patients and controls prostate hyperplasia and structural abnormalities were more frequent in acromegalics. After one year of treatment there was significant decrease in GH, IGF-I and prostate volume in acromegalics over 40 years-old.

CONCLUSIONS

Acromegalics under 40 have more urinary symptoms according to IPSS and above 40 years-old higher frequency of structural changes and increased prostate volume than healthy men. Significant reduction of GH and IGF-I levels during treatment of acromegaly leads to decrease in the prostate volume.

Genetic studies in a coexistence of acromegaly, pheochromocytoma, gastrointestinal stromal tumor (GIST) and thyroid follicular adenoma

We report on an adult woman with rare coexistence of acromegaly, pheochromocytoma (PHEO), gastrointestinal stromal tumor (GIST), intestinal polyposis, and thyroid follicular adenoma. At the age of 56, she was diagnosed with acromegaly caused by a pituitary macroadenoma, treated by transsphenoidal surgery, radiotherapy, and octreotide. During routine colonoscopy, multiple polyps were identified as tubular adenomas with high-grade dysplasia on histology. Years later, an abdominal mass of 8.0 x 6.2 cm was detected by routine ultrasound. Surgical exploration revealed an adrenal mass and another tumor adhered to the lesser gastric curvature, which were removed. Pathology confirmed the diagnosis of PHEO and GIST. PHEO immunohistochemistry was negative for GHRH. During follow-up, nodular goiter was found with normal levels of calcitonin and inconclusive cytology. Near-total thyroidectomy was performed, revealing a follicular adenoma. Her family history was negative for all of these tumor types. Genetic analysis for PHEO/paraganglioma genes (SDH A-D, SDHAF2, RET, VHL, TMEM127, and MAX), and pituitary-related genes (AIP, MEN1, and p27) were negative. Though the finding of PHEO and acromegaly with multiple other tumors could be a fortuitous coexistence, we suggest that this case may represent a new variant of MEN syndrome with a de novo germline mutation in a not yet identified gene.

Urinary calcium excretion and insulin resistance in patients with acromegaly

BACKGROUND

Renal complications in acromegaly include glomerular hyperfiltration, insulin resistance, hypercalciuria and urolithiasis. The aim of this study was to investigate whether urinary calcium (U(Ca)) excretion is a direct consequence of growth hormone secretion or secondary to hyperfiltration and/or insulin resistance.

METHODS

We performed a cross-sectional study of 58 patients diagnosed with acromegaly. Demographic data were obtained, serum analysis was performed, including insulin-like growth factor (IGF)-1, and 24-h urine collection, to measure urinary protein excretion, U(Ca) and phosphate excretion, as well as fractional excretion of sodium and potassium. We also calculated the homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

Patients were predominantly male (60.3%), and their mean age was 45.9 ± 14 years. Hypercalciuria was present in 24% of patients. Patients with higher HOMA-IR had higher IGF-1 levels, a trend toward higher body mass index and higher U(Ca) excretion. In univariate analysis, U(Ca) excretion was associated with HOMA-IR (r = 0.472, P = 0.001), phosphaturia (r = 0.457, P = 0.001), IGF-1 (r = 0.398, P = 0.002) and creatinine clearance (r = 0.394, P = 0.001). HOMA-IR and phosphaturia were independently associated with U(Ca) excretion. No independent associations were found between phosphaturia and HOMA-IR or IGF-1.

CONCLUSIONS

The present study revealed an association between hypercalciuria and insulin resistance in patients with acromegaly. Further studies are required to fully understand the pathogenesis of these abnormalities in patients with acromegaly.

Ectopic secretion of GHRH by a pancreatic neuroendocrine tumor associated with an empty sella

Acromegaly is usually the result of a pituitary growth hormone cell-adenoma or is more rarely due to ectopic secretion of growth hormone releasing hormone (GHRH).We report the case of a 60-year-old woman with acromegaly due to a GH-RH-secreting pancreatic tumor. Laboratory evaluation confirmed the diagnosis of acromegaly. Magnetic resonance imaging revealed a partial empty sella with no signs of adenoma. Ultrasound sonography performed for abdominal pains showed a calcified large heterogeneous infrahepatic mass. Computed tomography scan discovered a heterogeneous pancreatic head mass with a diameter of 10cm. Measurement of fasting plasma GHRH was performed showing a high concentration of 604ng/L (normal 10-60). We therefore concluded that the acromegaly was caused by ectopic overproduction of GHRH likely due to the pancreatic tumor. The patient underwent a cephalic duodenopancreatectomy. Histology revealed a well-circumscribed tumor with organoid architecture. Immunohistochemistry demonstrated diffuse positivity for chromogranin A, neuronal specific enolase and synaptophysin and negative immunoreactivity for prolactin, GH and serotonin. These features were concordant with a well-differentiated neuroendocrine tumor of the pancreas. Surgical resection of this pancreatic tumor was followed by significant amelioration of acromegalic signs and normalization of GHRH and GH levels.

Prostate cancer and acromegaly

Acromegalic patients have an increased prevalence of prostatic disorders compared to age-matched healthy subjects. Increased size of the whole prostate or the transitional zone, together with an elevated incidence of other structural changes, such as nodules, cysts, and calcifications, have been reported. Prostate enlargement in young acromegalic patients with low testosterone levels due to central hypogonadism supports the hypothesis that chronic GH and IGF-I excess cause prostate hyperplasia. The relationship between prostatic carcinoma and acromegaly is, until now, only circumstantial. Long-term follow-up of these patients is necessary since epidemiologic studies showed association between serum IGF-I levels in the upper normal limit and prostate cancer in the general population. This review approaches prostate diseases in patients with acromegaly.

Prevalence of sleep apnea and metabolic abnormalities in patients with acromegaly and analysis of cephalometric parameters by magnetic resonance imaging

OBJECTIVES

To determine the prevalence of sleep apnea (SA) and SA syndrome (SAS) in patients with acromegaly and correlate SA with clinical, laboratory, and cephalometric parameters.

DESIGN AND METHODS

Prospective and cross-sectional study of 24 patients with active acromegaly evaluated by clinical and laboratory (GH, IGF-I) parameters, polysomnography and magnetic resonance imaging (MRI) of the pharynx.

RESULTS

Out of 24 patients, 21 had SA (87.5%), of which 20 (95.3%) had the predominant obstructive type. Median age of these 21 patients was 54 years (range 23-75) and median estimated disease duration was 60 months (range 24-300). The frequency in SA patients of impaired glucose tolerance, diabetes mellitus (DM), and hypertension was 19, 33.3, and 71.4% respectively. Goiter was found in 10 patients (47.6%) and obesity in 18 (90%). Median GH level was 14 mug/l (1.4-198) and median %IGF-I (percentage above the upper limit of normal range of IGF-I) was 181% (-31.6 to 571.2). The prevalence of SAS was 52.4%. Apnea-hypopnea index (AHI) correlated significantly with age, waist circumference, body mass index, and hypopharynx area. The AHI was significantly higher in patients with hypertension and DM.

CONCLUSIONS

The prevalence of SA and SAS in acromegaly was similar to the one previously described in other series. Age was a significant risk factor, and hypertension and DM were significantly associated complications of SA. Obesity was also significantly related to SA, as a risk factor, a complication or both. Overall, cephalometric parameters by MRI did not correlate with SA.

Substantial Shrinkage of Adenomas Cosecreting Growth Hormone and Prolactin with use of Cabergoline Therapy

OBJECTIVE

To present 2 cases of patients with acromegaly and severe hyperprolactinemia whose primary therapy with cabergoline resulted in hormonal normalization and a considerable reduction in the size of their somatotroph macroadenomas.

METHODS

We summarize the clinical presentation and the pertinent laboratory findings in 2 patients with acromegaly, as well as their clinical response to the therapy with cabergoline. A review of the literature regarding the use of cabergoline in acromegaly is also presented.

RESULTS

A 48-year-old man (case 1) and a 26-year-old woman (case 2) were found to have acromegaly associated with very high levels of serum prolactin (2,700 and 5,250 ng/mL, respectively). These patients received first line therapy with cabergoline that resulted not only in clinical improvement and normalization of growth hormone, prolactin, and insulin-like growth factor-I levels but also in a substantial reduction in the size of their somatotroph macroadenomas. By 6 months after the patients began to take cabergoline, tumor shrinkage of 94% (in case 1) and of 70% (in case 2) was demonstrated by magnetic resonance imaging.

CONCLUSION

Our findings demonstrate that cabergoline should be considered for medical treatment of adenomas cosecreting growth hormone and prolactin, even in the presence of large tumors with appreciable suprasellar extension, because substantial tumor shrinkage is possible with this therapy.

Acromegaly secondary to growth hormone-releasing hormone secreted by an incidentally discovered pheochromocytoma

Ectopic growth hormone-releasing hormone (GHRH)-secreting tumors are rare and cause acromegaly with somatotroph hyperplasia. We report a case of acromegaly secondary to GHRH secretion by an incidentally discovered pheochromocytoma in a normotensive patient. A 23-year-old man presented with signs and symptoms of acromegaly. Laboratory evaluation confirmed the diagnosis and magnetic resonance imaging (MRI) revealed a sellar mass which was thought to be a macroadenoma and surgically resected. The patient was not cured and medical treatment was indicated. An abdominal ultrasound performed before initiation of medical treatment showed a solid/cystic lesion superiorly to the right kidney. An abdominal MRI confirmed an adrenal tumor. Hormonal workup of the adrenal incidentaloma revealed elevated urinary catecholamine and total metanephrines findings strongly suggestive of a pheochromocytoma. Acromegaly was then suspected to be due to ectopic secretion of GHRH by the tumor. Patient underwent surgical resection and histopathologic examination confirmed a pheochromocytoma which stained positively for GHRH. Also, review of the pituitary specimen confirmed somatotrophic hyperplasia. Genetic analysis of the ret proto-oncogene showed no mutation. Pituitary MRI was repeated 10 months after pheochromocytoma resection and revealed a slightly enlarged pituitary and partial empty sella. The diagnosis of acromegaly caused by ectopic production of GHRH is a challenging task. A careful histopathological examination of the surgically excised pituitary tissue has a key role to arouse the suspicion and guide the investigation of a secondary cause of acromegaly.