Treatment Of Pituitary Adenomas Research Articles

Evaluation of Complications and Costs During Overlapping Transsphenoidal Surgery in the Treatment of Pituitary Adenoma.

Evaluation of Complications and Costs During Overlapping Transsphenoidal Surgery in the Treatment of Pituitary Adenoma.

International Union of Basic and Clinical Pharmacology. CV. Somatostatin Receptors: Structure, Function, Ligands, and New Nomenclature.

Somatostatin, also known as somatotropin-release inhibitory factor, is a cyclopeptide that exerts potent inhibitory actions on hormone secretion and neuronal excitability. Its physiologic functions are mediated by five G protein–coupled receptors (GPCRs) called somatostatin receptor (SST)1–5. These five receptors share common structural features and signaling mechanisms but differ in their cellular and subcellular localization and mode of regulation. SST2 and SST5 receptors have evolved as primary targets for pharmacological treatment of pituitary adenomas and neuroendocrine tumors. In addition, SST2 is a prototypical GPCR for the development of peptide-based radiopharmaceuticals for diagnostic and therapeutic interventions. This review article summarizes findings published in the last 25 years on the physiology, pharmacology, and clinical applications related to SSTs. We also discuss potential future developments and propose a new nomenclature.

The relation of pituitary adenomas invasiveness and the proliferative index measured by immunoexpression of topoisomerase IIα.

Cavernous sinus invasion by pituitary adenoma affects surgical procedure radicality and consequently the postoperative course and prognosis in pituitary adenoma treatment. The search for pituitary adenoma aggressive behaviour markers is still a matter of debate. This study evaluates the relation of pituitary adenoma invasiveness to the expression of topoisomerase IIα in 72 patients who underwent transsphenoidal pituitary surgery. The assessment of tumour growth was conducted according to the Hardy scale as modified by Wilson and the Knosp scale. Topoisomerase IIα expression in tumour specimens was evaluated using immunohistochemical staining. There was a correlation between the Knosp scale degree and the topoisomerase IIα expression (Spearman R = 0.3611, p < 0.005). The Kruskal-Wallis H test (p = 0.0034) showed that there was a statistically significant topoisomerase IIα expression increase in tumours classified as grade E on the Hardy scale. The topoisomerase IIα expression correlated also with tumour size (Spearman R = 0.4117, p < 0.001). Higher levels of expression were observed in macroadenomas, as compared to microadenomas (p < 0.05, Mann-Whitney test). Topoisomerase IIα expression correlated with cavernous sinus invasion. The topoisomerase IIα expression correlated more with invasiveness than with extensiveness, which might make it an eminently useful marker in the assessment of aggressive pituitary adenoma behaviour.

A Comparative Study of Endoscopic Versus Navigation Guided Microscopic Transsphenoidal Pituitary Surgery at Tertiary Care Centre in India

Abstract Introduction: The transsphenoidal route for pituitary surgery is considered the standard treatment for pituitary adenomas. The disadvantage of the smaller exposure of this route is partially compensated for by the introduction of the microscope with its coaxial illumination, stereoscopic view, adequate magnification, and microsurgical instruments. However, there are only few reports about the outcome of endonasal endoscopic transphenoidal technique. Aims &amp; Objectives: Current study has been conducted to compare the efficacy, advantages and dis advantages of endoscopic versus navigation guided microscopic transsphenoidal Pituitary surgery. Material and methods: A controlled study was done in the department of neurosurgery, at tertiary care hospital in India, from the period of August 2012 to December 2017 prospectively. In Group A- 30 patients in whom endoscopic transnasal trans Sphenoidal pituitary surgery and in Group B - 30 patients, intraoperative neuronavigation was used. Observations and Results: Both the groups were similar in demographic variables. The most common age group of pituitary tumor patients was 30-40 years. Fourteen (46.6 %) patients in group A and fifteen (50 %) of the patients in group B had tumor volume less than 5 ml. In group A, thirteen (43%) patients had intrasellar tumors with no suprasellar extension, while in group B, fifteen (50%) patients had intrasellar tumors with no extension. Operative time was noted from incision to closure and average time taken in both the groups was compared. Twenty five (83%) cases of group A took between 2-3 hours and only four cases (13%) took more than 3 hours. While in group B, twenty (66%) cases took between 4-5 hours. This shows a significant difference by fisher extact test (p&lt;0.001) in the operative time required in both the groups. Eighteen (60%) patients in group B had a residual volume between 1-1.5 ml while only two patients in group A had so. This difference is also significant Fischer Exact test (p&lt;0.001). Four (13.3%) patients in group A had diabites insipidus while only half of this, i.e. two (6.6%) had so in group B. however this difference in postoperative complication rate is not statistically significant between two groups. Conclusion: The results of our study correlate with many previous studies to compare endoscopic and microscopic transsphenoidal surgery. These two approaches are equally efficacious in oncological outcomes and the complication rates are comparable.

Pediatric pituitary adenomas in Northeast Mexico. A follow-up study

PurposeTo review incidence, treatment and outcome of pediatric pituitary adenomas (PAs).MethodsA follow-up study patients with the age of ≤19 years old who were treated from 1995 to 2015 in Mexico.ResultsOut of 1244 diagnosed PA, 43 patients were children (35 females, 8 males) with a mean age of 17.2 years. The majority were macroadenomas (70%) with prolactinomas (PRL) dominating (63%) followed by non-functioning adenomas (21%). In total, 40% were diagnosed as invasive. Growth hormone (GH) secreting adenomas, adrenocorticotropic hormone secreting and mixed GH-PRL secreting were rare. The treatment modalities were dopamine agonists and surgery. The average treatment time was 44 months with an average follow-up period of 104 months. Sixty-eight percent (27/40) of the patients had complete response after long time follow-up. Thirty-one percent did not respond to treatment whereof three patients died due to advanced disease and late intervention. The principal causes for treatment failure were treatment resistance, late intervention and poor patient compliance.ConclusionsSixty eight percent had complete treatment response without any sign of disease, while ~31% did not respond to treatment or did not comply to follow up/treatment. Optimized early diagnose, treatment methods with early intervention, long time follow-up and with better measures for patient compliance should improve outcomes.

Upregulation of Connexin-43 is Critical for Irradiation-induced Neuroinflammation.

Radiation therapy is widely used for the treatment of pituitary adenomas. Unfortunately, it might raise the risk of ischemic stroke, with neuroinflammation being a major pathological process. Astrocytes are the most abundant cell type in the central nervous system and have been reported for playing important roles in ischemic stroke. Here we studied how γ-radiation would introduce astrocytes into a detrimental state for neuroinflammation and provide new theory evidence and target for the clinical management of inflammation- related neural damage after radiation-induced ischemic stroke. HA-1800 cells were treated with γ-radiation and then the protein and mRNA levels of Connexin (Cx)-43 were evaluated by western and q-PCR. The culture supernatant was collected and the concentrations of the inflammatory factors were determined by ELISA. MiRNA complementary to Cx-43 was designed through the online tools. Cx-43 is upregulated in the treatment of γ-radiation in astrocytes and γ-radiation introduced the detrimental function of astrocytes: cell viability was reduced while the apoptotic cells were increased. Inflammatory factors like tumor necrosis factor alpha, interferon gamma, interleukin-6, interleukin 1-beta were dramatically up-regulated by the irradiation. MiR-374a rescued irradiation induced Cx-43 up-regulation of astrocytes and eliminated detrimental function triggered by γ-radiation. Cx-43 expression level may play an important role in the inflammation-related neural damage after irradiation-induced ischemic stroke.

Immunotherapy and potential molecular targets for the treatment of pituitary adenomas resistant to standard therapy: a critical review of potential therapeutic targets and current developments

Pituitary adenomas (PAs) are primary central nervous system (CNS) tumors, accounting for as much as 25% of intracranial neoplasms. Although existing remedies show success in treating most PAs, treatment of invasive and non-functioning PAs, in addition to functioning PAs unresponsive to standard therapy, remains challenging. With the continually increasing understanding of biochemical pathways involved in tumorigenesis, immunotherapy stands as a promising alternative therapy for pituitary tumors that are resistant to standard therapy. A literature search was conducted of the PubMed database for immunotherapies of PAs. The search yielded a total of 2621 articles, 26 of which were included in our discussion. Several pathologically expressed molecules could potentially serve as promising targets of current or future immunotherapies for PAs. Programmed death ligand-1, matrix metalloproteinases, EpCAM (Trop1) and Trop2, cancer-testis antigen MAGE-A3, epidermal growth factor receptor (EGFR), folate receptor alpha, vascular endothelial growth factor, and galectin-3 have all been implicated as crucial factors involved with tumor survival and invasion. Inhibition of these pathways may prove efficacious in the management of invasive and treatment-resistant PAs. Rapid advancements in tumor immunology may increase the probability of successful treatment of PAs by exploitation of the normal immune response or by targeting novel proteins. Current research on many of the targets reviewed in this article are successfully being utilized to manage various neoplastic disease including CNS tumors. These therapies may eventually play a key role in the treatment of PAs that do not respond to standard therapy.

Overexpression of microRNA-34a Attenuates Proliferation and Induces Apoptosis in Pituitary Adenoma Cells via SOX7

Pituitary adenomas constitute one of the most common intracranial tumors and are typically benign. However, the role of the tumor suppressor microRNA-34a (miR-34a), which is implicated in other cancers, in pituitary adenoma pathogenesis remains largely unknown. miR-34a expression was compared between GH4C1 cancer cells and normal cells derived from the pituitary gland of Rattus norvegicus, and the effects of miR-34a on GH4C1 cell proliferation and apoptosis were examined. miR-34a target genes were identified and analyzed computationally. The mRNA levels of the miR-34a target genes were measured using qRT-PCR, and the protein levels of the differentially expressed targets were assessed by western blotting. miR-34a expression was significantly lower in GH4C1 cells, whereas miR-34a overexpression significantly inhibited GH4C1 cell proliferation and promoted cell apoptosis though SRY-box 7 (SOX7). Our data facilitate the development of a better understanding of the pathogenesis and treatment of pituitary adenomas by elucidating the crucial role of miR-34a in the development of pituitary adenomas.

Postoperative Complications Of Endoscopic Versus Microscopic Transsphenoidal Pituitary Surgery: A Meta-analysis

Transsphenoidal microscopic pituitary surgery is an effective way of treating pituitary tumors. However, minimal invasive approach endoscopic transsphenoidal pituitary surgery has become much more prevalent these days. Endoscopic surgery resects the maximum tumour with less complications. As endoscopic surgery is much safer and less invasive as compared to the microscopic transsphenoidal surgery, selection of technology for the treatment of pituitary adenoma is becoming increasingly equivocal. The main aim of this systematic review was to assess the safety of endoscopic and microscopic transsphenoidal pituitary surgery in terms of postoperative complications. Relevant studies between January 1992 and January 2017 were searched in the Cochrane Library electronic databases, EMBASE and MEDLINE, through a systematic literature search. A total of 1,463 patients reviewed (microscopic group=684, endoscopic group=779), the proportion of diabetes insipidus, septal perforation and other complications related to surgery (include lip anesthesia, nasal anesthesia, deviated septum, saddle nose, sinusitis, synechiae, anosmia) in those patients who had endoscopic surgery were significantly lower (p<0.05). No significant difference emerged between the two approaches in the incidence rates of cerebrospinal fluid leak, meningitis, epistaxis or hypopituitarism (p>0.05). These results support the safety of endoscopic transsphenoidal pituitary adenoma surgery.

Spectrum of Pituitary disorders: A retrospective study from Basrah, Iraq.

Background: Pituitary disorders spectrum includes a wide variety of diseases.This study aimed at a comprehensive description of such disorders for patients from Faiha Specialized Diabetes, Endocrine and Metabolism Center (FDEMC) in Basrah (Southern Iraq). Methods:Retrospective data analysis of FDEMC for the period from January 2012 through June 2017. We included all patients with pituitary disorders who have MRI pituitary. Results:The pituitary disorders were more common among women. Those with macroadenoma were older than those with microadenoma with nearly equal gender prevalence of macroadenoma. Pituitary adenoma constituted the bulk of pituitary disorders in this registry (67.2%). Growth hormone secreting adenoma were the commonest adenoma seen in 41.0% followed by clinically non-functioning pituitary adenoma(NFPA)in 31.4% and prolactinoma in 26.9%. About 64.8% of pituitary adenoma was macroadenoma. Macroadenoma was seen in 73.4 % of growth hormone secreting adenoma, 61.2% in NFPA and 62.0% of prolactinoma (of them six were giant prolactinoma) Conclusion: Pituitary adenoma constituted the bulk of pituitary disorders in Basrah, growth hormone secreting adenoma is the commonest adenoma followed by NFPA and prolactinoma due to referral bias. A change in practice of pituitary adenoma treatment is needed.

Epithelial–Mesenchymal Transition Induced by SMAD4 Activation in Invasive Growth Hormone-Secreting Adenomas

Abstract Background The detection and treatment of invasive growth hormone-secreting pituitary adenoma (GHPA) remains challenging. Several transcription factors promoting the epithelial–mesenchymal transition (EMT) can act as cofactors for the transforming growth factor-beta (TGF-ß)/SMAD4. The goal of this study was to investigate the association of SMAD4 expression and clinicopathologic features using a tissue microarray analysis (TMA). The levels of SMAD4 and the related genes of EMT in GHPAs were analyzed by q-PCR and western blot. SMAD4 was strongly expressed in 15/19 cases (78.9%) of invasive GHPA and 10/42 cases (23.8%) of noninvasive GHPA (χ2=10.887, p=0.000). In the high SMAD4 group, a headache was reported in 16/25 cases (64%) compared with 13/36 cases (36.1%) in the low SMAD4 group (χ2=4.565, p=0.032). The progression-free survival (PFS) in the high group was lower than that in the low group (p=0.026). qRT-PCR and western blot analysis further revealed a significant downregulation of E-cadherin and upregulation of N-cadherin and vimentin in the invasive GHPA group. SMAD4 was associated with increased levels of invasion of GH3 cells, as determined by a transwell test. SMAD4 downregulated E-cadherin levels and increased the levels of N-cadherin and vimentin. Our data provide evidence that SMAD4 is a potential prognosis biomarker and a therapeutic target for patients with invasive GHPA.

C.04 A systematic review and meta-analysis of 7551 patients with post-operative radiation for the management of functioning and non-functioning pituitary adenomas

Background: Although surgery is the mainstay of treatment for most pituitary adenomas, post-operative radiotherapy has been shown to be of benefit in improving tumor control and recurrence-free survival. To understand potential side effects of radiotherapy we performed a systematic review and meta-analysis to determine the efficacy and safety of post-operative radiotherapy for pituitary adenoma. Methods: A systematic review was performed according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. We searched PubMed, MEDLINE and Cochrane databases with no language or publication date restrictions. Outcomes included 5- and 10-year progression-free survival and adverse events rates. Results: A total of 48 studies from 1986-2016 met the inclusion criteria, with 7551 cumulative patients. The cumulative 5- and 10-year s progression-free survival rates were 90.8% (95% CI 86-94%) and 88.6% (95% CI 81-93%), respectively. The overall adverse events rate was 8% (95% CI 5-12%). All outcomes were associated with significant heterogeneity (I2 ≥ 70%). No differences in survival rates or adverse events in relation to study date, tumor pathology, radiosurgery system used or dose of radiation. Conclusions: Post-operative radiotherapy for pituitary adenomas is effective and safe. Because of the significant heterogeneity and lack of matched controls in the literature, optimum timing and dosage are still unclear. Further prospective studies are needed.

Regression of a nonfunctioning pituitary macroadenoma on the CDK4/6 inhibitor palbociclib: case report

A 71-year-old female patient was referred in 2013 for evaluation of an asymptomatic nonsecreting pituitary adenoma. The adenoma, measuring 13 mm in height by 10 mm in width, was discovered incidentally on imaging in 2012. Biochemical testing demonstrated a nonfunctioning adenoma. Given the relatively small lesion size and the lack of symptoms, observation was preferred over surgical intervention. The patient was monitored with routine MRI, which until 2016 demonstrated minimal growth. In early 2016, the patient developed recurrence of metastatic breast cancer and was treated with palbociclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor. This inhibitor acts on a pathway believed to be involved in pituitary adenoma tumorigenesis. One year after starting palbociclib, routine imaging demonstrated significant regression of her pituitary adenoma. The authors hypothesize that inhibition of the CDK4/6 pathway by palbociclib contributed to adenoma regression in this patient, and that palbociclib may represent a possible adjuvant therapy for the treatment of nonfunctioning pituitary adenomas.

P.055 Epidemiologic features of pituitary adenoma patients requiring surgical treatment: large North American patient population based study

Background: The surgical treatment of pituitary adenoma has evolved greatly over the decades. In order to better understand the patient population and their surgical treatment, we conducted an institutional review for pituitary adenoma surgery using the endoscopic endonasal trans-sphenoidal (EETS) approach. Methods: A retrospective review of all EETS cases for pituitary tumor resection was performed between November 2009 and June 2016. Patient characteristics, tumor type, endocrine data, operation characteristics were extracted from medical records. Preoperative MRI images were reviewed. The SIPAP classification was applied to the pituitary tumors. Postoperative patient data were extracted for the available follow-up period. Results: 232 cases were identified. Functional tumors were present in 29% of the cohort. Complete excision was most common for functioning tumors (49%) compared to nonfunctioning tumors (26%). There were no major vascular injuries. Hormone replacement with cortisol was required transiently in 70% of patients, with thyroid hormone replacement occurring in 40% of the cohort. Conclusions: From this large North American cohort nearly 30% of operated pituitary tumors were functioning. More commonly, these tumors were completely resected compared to the nonfunctioning group. The most commonly replaced hormone following EETS surgery was cortisol and this was largely transient.

Stereotactic radiation therapy for the treatment of functional pituitary adenomas associated with feline acromegaly.

BackgroundConventional fractionated radiotherapy has been shown to be partially effective for management of pituitary tumors in cats that cause acromegaly and diabetes mellitus (DM), but, the efficacy and safety of stereotactic radiation therapy (SRT) as a treatment for acromegalic cats has not been described.HypothesisStereotactic radiation therapy is an effective and safe treatment for controlling acromegaly associated with pituitary adenomas in cats. Additionally, SRT‐treated acromegalic cats with DM will experience a decrease in insulin requirements after radiation therapy.AnimalsFifty‐three client‐owned cats referred to Colorado State University for SRT to treat pituitary tumors causing poorly controlled DM secondary to acromegaly.MethodsRetrospective study of cats treated for acromegaly with SRT between 2008 and 2016 at Colorado State University. Diagnosis of acromegaly was based on history, physical examination, laboratory results, and cross‐sectional imaging of the pituitary. Signalment, radiation protocol, insulin requirements over time, adverse effects, and survival were recorded.ResultsMedian survival time was 1072 days. Of the 41 cats for which insulin dosage information was available, 95% (39/41) experienced a decrease in required insulin dose, with 32% (13/41) achieving diabetic remission. Remission was permanent in 62% (8/13) and temporary in 38% (5/13) cats. Median duration to lowest insulin dose was 9.5 months. Of the treated cats, 14% developed hypothyroidism and required supplementation after SRT.ConclusionsStereotactic radiation therapy is safe and effective for treating cats with acromegaly. Cats treated with SRT have improved survival time and control of their DM when compared to previously reported patients treated with non‐SRT.

Endonasal endoscopic surgery in pituitary adenomas: Surgical results in a series of 86 consecutive patients

IntroductionThe endoscopic endonasal approach has become the gold standard for the surgical treatment of pituitary adenomas. ObjectivesThe aim of this study is to present the results obtained in our hospital in purely endoscopic surgery of pituitary adenomas. MethodsFrom February 2011 to August 2016, we conducted a prospective study on a series of 86 patients with pituitary adenoma, all of whom underwent surgery with a purely endoscopic endonasal approach. The ‘four hands-two nostrils’ technique was performed in all cases by a surgical team composed of an ENT surgeon and a neurosurgeon. Mean follow-up was 32 months. All patients were evaluated according to clinical, radiological and endocrinological criteria. ResultsIn our series, 53% were women and 47% men. The age ranged from 14 to 84 years of age, with a mean of 54 years of age. The most common initial symptom was visual deficit (42%), followed by hormonal hyperfunction (21%), with acromegaly being the most common clinical syndrome. The most common tumours were non-functioning tumours (73%), while GH-secreting tumours (65%) were the most common functioning adenoma. Regarding tumour size, 76% were macroadenomas, 11% microadenomas and 13% giant adenomas. Approximately 63% of the adenomas exhibited suprasellar extension and 37% involved invasion of the cavernous sinus (Knosp grade ≥3). Total excision was achieved in 77% of the cases. After the intervention, visual improvement was achieved in 91% and remission of endocrine hyperfunction in up to a 73% of cases. The most common complication was anterior pituitary insufficiency of at least one axis (9%). There were no cases of postoperative cerebrospinal fluid fistula. ConclusionsIn terms of surgical quality, our results are similar to those of published series, and demonstrate the efficacy and safety of the endoscopic endonasal approach as the surgical treatment of choice for pituitary adenomas. However, further studies with a higher sample size are necessary to obtain clinically significant results.

Spectrum of Pituitary disorders: A retrospective study from Basrah, Iraq

Background: Pituitary disorders spectrum includes a wide variety of diseases.This study aimed at a comprehensive description of such disorders for patients from Faiha Specialized Diabetes, Endocrine and Metabolism Center (FDEMC) in Basrah (Southern Iraq). Methods: Retrospective data analysis of FDEMC for the period from January 2012 through June 2017. We included all patients with pituitary disorders who have MRI pituitary. Results: The pituitary disorders were more common among women. Those with macroadenoma were older than those with microadenoma with nearly equal gender prevalence of macroadenoma. Pituitary adenoma constituted the bulk of pituitary disorders in this registry (67.2%). Growth hormone secreting adenoma were the commonest adenoma seen in 41.0% followed by clinically non-functioning pituitary adenoma(NFPA)in 31.4% and prolactinoma in 26.9%. About 64.8% of pituitary adenoma was macroadenoma. Macroadenoma was seen in 73.4 % of growth hormone secreting adenoma, 61.2% in NFPA and 62.0% of prolactinoma (of them six were giant prolactinoma) Conclusion: Pituitary adenoma constituted the bulk of pituitary disorders in Basrah, growth hormone secreting adenoma is the commonest adenoma followed by NFPA and prolactinoma due to referral bias. A change in practice of pituitary adenoma treatment is needed.

Volumetry in the Assessment of Pituitary Adenoma Resection: Endoscopy versus Microscopy

Background Assessment of the extent of resection after surgical resection of pituitary adenomas is most commonly reported in terms of the presence or absence of residual tumor. A quantitative comparison of volumetric resection between endonasal endoscopy (EE) and microsurgery (MS) has rarely been done. Methods A retrospective analysis was performed on a consecutive series of 154 patients with pituitary adenomas treated by the same surgeon at a single institution. We employed volumetric analysis pre- and postoperatively on two cohorts of pituitary adenoma patients treated through MS ( n = 37) versus EE approach ( n = 117). Results Volumetric analysis revealed a higher incidence of complete resection (64.4 vs. 56.8%) and mean volume reduction in the EE cohort (92.7 vs. 88.4%), although not significant. Recurrence rates were significantly lower in the EE group (7.7% vs 24.3%, p = 0.015). Subgroup analysis identified that patients with preoperative tumor volumes >1 mL were less likely to recur through EE (7.8 vs. MS: 29.6%; p = 0.0063). A higher incidence of complete resection was also noted in patients with favorable Knosp grades (0-1) (EE: 87.8 vs. MS: 63.2%; p = 0.036). Postoperative complication rates were not significantly different between both techniques. Conclusion Both microscopy and endoscopy are well-tolerated, effective approaches in the treatment of pituitary adenomas. Our series demonstrated that EE may be superior to MS in preventing tumor recurrence and achieving a complete resection in certain subsets of patients. EE provides a slight advantage in tumor control outcomes that may justify the paradigm shift to pure endoscopy at our center.

Evaluation of dose profiles using Gafchromic EBT3 films in Leksell Gamma Knife 4C around inhomogeneities in the treatment of pituitary adenoma in anthropomorphic heterogeneous head phantom

PurposeThe Leksell Gamma Knife is a complete system for radiosurgery. Treatment dose planning of Gamma Knife assumes the human head as a homogenous media; thus received dose by target tissue and organs at risk may be lower or higher than predicted dose. Our main interest is to compare measured dose profiles in an anthropomorphic heterogeneous head phantom by EBT3 films with calculated dose by Leksell Gamma Plan. MethodsAn adult head phantom with size, shape and inhomogeneity the same as an adult human head was constructed. Then dose profiles across from isocenter and organs at risk were measured by EBT3 films and compared with those predicted by Leksell Gamma Plan. ResultsOur findings indicate that when isocenter placed at the target tissue near the frontal sinus cavity, overestimation and underestimation of the dose value affect the dose profiles. In some points of organs at risk, measured dose is more than calculated dose. Comparison of isodose curves near air-tissue interface shows that in higher isodose levels, dose perturbation is more seen. Distance to Agreement parameter for some isodose lines exceeds the total positioning error for Gamma Knife (± 2 mm). Also dose differences are more than numerical accuracy in dose delivery for stereotactic radiosurgery (± 5%). ConclusionsInhomogeneities in head impress dose distributions. Ignorance of inhomogeneities can cause the parts of target tissue receive under dosage and also in some points, organs at risk receive more dose. Results of this study are closer to reality because of anthropomorphic heterogeneous head phantom.

Radiation-associated Pituitary Sarcoma

Background: Radiation therapy is commonly used as primary or adjuvant treatment for pituitary adenomas. Frequent side effects of this modality include hypopituitarism, visual disturbances, short-term memory loss and secondary tumors, sarcomas being among the rarest of the sellar region, with only 55 reported cases to date. Clinical Presentation: A 57-year old man with hypopituitarism and a 20-year history of a non-functioning pituitary macroadenoma subtotally resected four times and undergoing whole brain radiotherapy and bromocriptine, who developed acute visual deterioration due to compression of the optic chiasm by rapid growth of the residual tumor. An endoscopic transplanum approach was performed achieving gross total resection. Histopathological examination was consistent with an undifferentiated low-grade pituitary sarcoma. The patient’s vision improved after surgery, but healthcare-associated complications compromised his clinical outcome, succumbing to a pulmonary embolism a month after surgery. Conclusion: Radiation-induced pituitary sarcoma is a very rare complication of radiotherapy. There is no distinctive feature on imaging that can predict its occurrence. Prognosis is grim, without effective management and a mean survival of 6.5 months after diagnosis.