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pituitary_adenoma

Pituitary adenoma

Pituitary adenoma (PA) is a common pituitary tumor that arise from the adenohypophysis, in the pituitary gland.

Epidemiology

The overall prevalence in the general US population is estimated at 16.7% 1).

Overview of demographic characteristics in Iranian patients

278 patients with PAs who underwent surgical interventions were evaluated. Most of the patients were aged 40-50 years with an average of 41 ± 14. The most prominent complaint was pressure effect, which was detected in 153 cases (55.2%). At the second place, hormonal disorders were observed in 125 cases (44.8%). Type of pituitary tumors were: Prolactinomas (29.1%), growth hormone (GH)-producing tumors (25%), nonfunctioning PAs (28.4%), adrenocorticotropic hormone (ACTH)-producing tumors (2.1%), thyroid stimulating hormone (TSH)-producing tumors (0.7%), GH/prolactin (13.6%), GH/ACTH (0.3%), and TSH/ACTH (0.3%). Fifty-seven patients presented with recurrent adenomas. Pituitary apoplexy was found in 11 patients. One case of Sheehan syndrome was recorded among these. The correlations between clinical symptoms and patients, age and sex were not significant 2).

Classification

The classification is based upon size, invasion of adjacent structures, sporadic or familial cases, biochemical activity, clinical manifestations, morphological characteristics, response to treatment and recurrence 3).

Current classification systems for PAs are based primarily on secretory characteristics of the tumor but are also classified on the basis of phenotypical characteristics, including tumor size, degree of invasiveness (e.g., Knosp grade), and immunohistological findings 4).

The WHO classification system for PAs has been refined to include designations for benign adenoma, atypical pituitary adenoma, and pituitary carcinoma on the basis of p53 immunoreactivity, MIB-1 index, mitotic activity, and the absence/presence of metastases 5) 6).

Types

These tumor types can be microadenomas or macroadenomas and can either be functional or non-functional.

By Size

Pituitary microadenoma

Pituitary macroadenoma

Giant pituitary adenoma

Volume can be calculated using MRI-guided volumetrics and an ellipsoid approximation (TV × AP × CC/2) transverse (TV), antero-posterior (AP) and cranio-caudal (CC).

By Function

Functioning pituitary adenoma

Nonfunctioning pituitary adenoma

Pituitary adenomas with gangliocytic component are rare tumors of the sellar region that are composed of pituitary adenoma cells and a ganglion cell component. Their histogenesis and hence nosology is not yet resolved because of the small number of cases reported and lack of large series in the literature 7).

Invasive pituitary adenomas and pituitary carcinomas are clinically indistinguishable until identification of metastases.

Clinical features

The relationship between headaches, pituitary adenomas, and surgical treatment of pituitary adenomas remains unclear.

Surgery can significantly improve headaches in patients with pituitary adenomas by 6 months postoperatively, particularly in younger patients whose preoperative QOL is impacted. A larger multicenter study is underway to evaluate the long-term effect of surgery on headaches in this patient group 8).

Diagnosis

MRI is commonly used in the evaluation of pituitary adenomas (PAs). However, it has difficulty to locate the lesions sometimes, especially microadenomas and/or postoperative recurrent tumors.

Positron emission tomography/CT may be useful to detect tumors in patients with equivocal MRI results.

11C methionine positron emission tomography PET/CT can provide valuable diagnostic information when F-FDG PET/CT yields negative results, especially in patients with recurrent microadenomas 9).

Treatment

Perioperative management

Though randomized controlled trials (RCT) have not been performed to assess the necessity of steroid coverage, there are several studies that explained the changes of adrenal function during peri-operative peroids.

Studies addressing peri-operative steroids coverage for pituitary adenomas in the Web of Science, Medline and the Cochrane Library and extracted studies about perioperative morning serum cortisol (MSC) levels, morbidity of early postoperative adrenal insufficiency, postoperative diabetes insipidus, relationships between MSC levels and adrenal integrity.

There are 18 studies from 11 countries published between 1987 and 2013 including 1224 patients. The postoperative serum cortisol levels were significantly increased compared with the preoperative one in hypothalamic-pituitary-adrenal axis(HPAA) functions preserved patients(P<0.00001). The morbidity of early postoperative adrenal insufficiency ranged from 0.96% to 12.90%, with the overall morbidity of 5.55%(41/739). There was no significant differences of early postoperative diabetes insipidus between no supplementation patients and in supplementation patients(P=0.82). Conversely, there may be some disadvantages of high levels of cortisols such as high incidence of osteopenia and bone derangement and even the increased mortality rate. The patients with MSC levels of less than 60 nmol/l at 3 days after operation is considered as adrenal insufficient and more than 270 nmol/l as adrenal sufficient. To patients with MSC levels of 60-270 nmol/l, we need more clinical data to establish further cortisol supplementation criteria 10).

Outcome

Although they are considered benign tumors, some of them are difficult to treat due to their tendency to recur despite standardized treatment. Functional tumors present other challenges for normalizing their biochemical activity. Novel approaches for early diagnosis, as well as different perspectives on classification, may help to identify subgroups of patients with similar characteristics, creating opportunities to match each patient with the best personalized treatment option 11).

Case series

2017

A total of 160 patients who underwent surgical resection of pituitary adenomas between February 2004 and December 2016 were reviewed. Eighty-one patients had hormone-secreting pituitary adenomas, and 79 patients had nonfunctioning pituitary adenoma. Among these 160 patients, cases with radiological calcifications on preoperative neuroimaging were included in this study, and clinical characteristics with intraoperative findings were analyzed, retrospectively.

Pituitary adenoma with calcification on preoperative neuroimaging was observed in only nine cases (5.6%). The study population consisted of these nine patients with nonfunctioning pituitary adenoma (n = 5), mixed growth hormone and prolactin-secreting pituitary adenomas (n = 3), and a prolactinoma (n = 1). In 89% of cases (n = 8), calcified pituitary adenoma was soft enough for suction despite the presence of a granular gritty texture intraoperatively. Besides, in a single patient (11%), evidence of hard thick capsular calcification was seen surrounding a soft tumor component; however, it did not interfere with adequate removal of the soft part, and tumor resection was possible in all cases without any complications.

Pituitary adenoma presenting with calcification is relatively rare, but should be kept in mind to avoid making a wrong preoperative diagnosis. As not all pituitary adenomas with calcification are hard tumors, preoperative radiological calcification should not affect decision-making regarding surgical indications 12).


Between 2004 and 2014, 94 patients with pituitary tumors were enrolled in this retrospective study. All patients underwent transsphenoidal surgery and received magnetic resonance imaging (MRI). The pre- and postoperative volumes calculated using the traditional formula were termed A1 and A2, and those calculated using the proposed method were termed O1 and O2, respectively. Wilcoxon signed rank test revealed no significant difference between the A1 and O1 groups (P = 0.1810) but a significant difference between the A2 and O2 groups (P < 0.0001). Significant differences were present in the extent of resection (P < 0.0001), high-grade cavernous sinus invasion (P = 0.0312), and irregular shape (P = 0.0116). Volume is crucial in evaluating tumor status and determining treatment. Therefore, a more scientific method is especially useful when lesions are irregularly shaped or when treatment is determined exclusively based on the tumor volume 13).

2016

Thirty patients with pituitary adenoma were recruited from Huashan Hospital between September 2010 and January 2014. The examination included pupil examination, anterior and posterior segment examination, standard automated perimetry (SAP), RNFL and mfVEP. At three months and nine months after transsphenoid surgery, follow-up measurements were conducted in twenty-three patients, and at 18 months after surgery, the same examinations were performed in seven patients.

The average age of patients was 42.6±12.1years, with 23 males and 7 females. The mean score of SAP improved significantly: 1.75 before surgery; 0.62 at three months after surgery (p=0.00) and 0.50 at nine months after surgery (p=0.00). No significant improvement in RNFL thickness was observed at three months or nine months after surgery. The mean score of mfVEP also improved significantly: 0.85 before surgery; 0.53 at three months (p=0.00) and 0.38 at nine months after surgery (P=0.00). No statistical difference was observed in the outcome of patients at nine months of follow-up and 18 months of follow-up.

Visual field and mfVEP recovery with unchanged RNFL thickness was observed in patients after transsphenoid pituitary adenoma resection 14).


79 patients with pituitary adenomas underwent endoscopic transsphenoidal resection and completed the Headache Impact Test (HIT-6) and the 36-Item Short Form Health Survey (SF-36) QOL questionnaire preoperatively and at 6 weeks and 6 months postoperatively.

Preoperatively, 49.4% of patients had mild headache severity, 13.9% had moderate severity, 13.9% had substantial severity, and 22.8% had intense severity. Younger age and hormone-producing tumors predisposed greater headache severity, while tumor volume, suprasellar extension, chiasmal compression, and cavernous sinus invasion of the pituitary tumors did not. Preoperative headache severity was found to be significantly associated with reduced scores across all SF-36 QOL dimensions and most significantly associated with mental health. By 6 months postoperatively, headache severity was reduced in a significant proportion of patients. Of the 40 patients with headaches causing an impact on daily living (moderate, substantial, or intense headache), 70% had improvement of at least 1 category on HIT-6 by 6 months postoperatively, while headache worsened in 7.6% of patients. The best predictors of headache response to surgery included younger age, poor preoperative SF-36 mental health score, and hormone-producing microadenoma.

The results of this study confirm that surgery can significantly improve headaches in patients with pituitary adenomas by 6 months postoperatively, particularly in younger patients whose preoperative QOL is impacted. A larger multicenter study is underway to evaluate the long-term effect of surgery on headaches in this patient group 15).

2015

278 patients with PAs who underwent surgical interventions were evaluated. Most of the patients were aged 40-50 years with an average of 41 ± 14. The most prominent complaint was pressure effect, which was detected in 153 cases (55.2%). At the second place, hormonal disorders were observed in 125 cases (44.8%). Type of pituitary tumors were: Prolactinomas (29.1%), growth hormone (GH)-producing tumors (25%), nonfunctioning PAs (28.4%), adrenocorticotropic hormone (ACTH)-producing tumors (2.1%), thyroid stimulating hormone (TSH)-producing tumors (0.7%), GH/prolactin (13.6%), GH/ACTH (0.3%), and TSH/ACTH (0.3%). Fifty-seven patients presented with recurrent adenomas. Pituitary apoplexy was found in 11 patients. One case of Sheehan syndrome was recorded among these. The correlations between clinical symptoms and patients, age and sex were not significant.

The overview of demographic characteristics in Iranian patients with PAs with surgical indication has been discussed in the present investigation. The prevalence of different types of PAs and the most common clinical symptoms have been demonstrated 16).

1)
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4)
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5)
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8) , 15)
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9)
Feng Z, He D, Mao Z, Wang Z, Zhu Y, Zhang X, Wang H. Utility of 11C-Methionine and 18F-FDG PET/CT in Patients With Functioning Pituitary Adenomas. Clin Nucl Med. 2016 Mar;41(3):e130-4. doi: 10.1097/RLU.0000000000001085. PubMed PMID: 26646998.
10)
Tohti M, Li J, Zhou Y, Hu Y, Yu Z, Ma C. Is Peri-Operative Steroid Replacement Therapy Necessary for the Pituitary Adenomas Treated with Surgery? A Systematic Review and Meta Analysis. PLoS One. 2015 Mar 16;10(3):e0119621. doi: 10.1371/journal.pone.0119621. eCollection 2015. PubMed PMID: 25775019.
12)
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13)
Chuang CC, Lin SY, Pai PC, Yan JL, Toh CH, Lee ST, Wei KC, Liu ZH, Chen CM, Wang YC, Lee CC. Different Volumetric Measurement Methods for Pituitary Adenomas and Their Crucial Clinical Significance. Sci Rep. 2017 Jan 18;7:40792. doi: 10.1038/srep40792. PubMed PMID: 28098212.
14)
Qiao N, Ye Z, Shou X, Wang Y, Li S, Wang M, Zhao Y. Discrepancy between structural and functional visual recovery in patients after trans-sphenoidal pituitary adenoma resection. Clin Neurol Neurosurg. 2016 Sep 6;151:9-17. doi: 10.1016/j.clineuro.2016.09.005. PubMed PMID: 27728836.
pituitary_adenoma.txt · Last modified: 2017/08/22 17:03 by administrador