Influence of preoperative medical treatment on the proliferative activity of pituitary adenomas in acromegaly

Die Akromegalie geht unbehandelt mit einer verkürzten Lebenserwartung einher. Daher ist das Ziel jeglicher Therapie die Normalisierung des Wachstumshormonexzesses. Neben der kausalen, operativen Therapie durch die Resektion des Wachstumshormon-produzierenden Tumorgewebes, stehen verschiedene Medikamente zur Behandlung zur Verfügung. Die Aufgabe dieser Arbeit war es, den Einfluss dieser Medikamente bzw. den einer Radiotherapie auf die immunhistochemische Expression der Proliferationsmarker Ki-67 und Topoisomerase-IIα von Wachstumshormon-sezernierenden Hypophysenadenomen von nicht vorbehandelten, primär operierten im Vergleich zu entsprechend behandelten Patienten zu untersuchen. Von besonderem Interesse war der Einfluss des Wachstumshormon-Rezeptor-Antagonisten Pegvisomant. Unter dieser Therapie kam es in einigen Fällen zu einem deutlichen Tumorprogress mit einmalig nachgewiesenem Anstieg der oben genannten Proliferationsparameter, die dem Wirkungsmechanismus des Medikaments zugeordnet wurden. Insgesamt standen 385 in Formalin fixierte Tumorproben von 368 Patienten zur retrospektiven Analyse der in den Jahren 2002 bis 2010 operierten Patienten zur Verfügung. Die Präparate wurden für die Proliferationsmarker Topoisomerase-IIα und Ki-67 gefärbt und die Proliferationsrate an allen Tumorproben mikroskopisch anhand der positiv gefärbten Zellen bestimmt. Diese Ergebnisse wurden mit den klinischen Parametern sowie der Art, Dauer und Dosis der medikamentösen Vorbehandlung in Beziehung gesetzt. Grundsätzlich verhielten sich die untersuchten Proliferationsparameter kongruent zu einander. Es fanden sich statistisch signifikant erhöhte Proliferationsraten bei größeren und invasiven Hypophysenadenomen bzw. jüngeren Patienten. Die Gabe von Dopamin-Agonisten und Somatostatin-Analoga führten zu einer Minderung beider Proliferationsparameter, wobei die Applikationsdauer bzw. die Dosierung der Medikamente keinen signifikanten Einfluss zeigten. Einzig Oktreotid führte aber auch nur in der Gruppe der dicht-granulierten Hypophysenadenome zu einer statistisch signifikanten Minderung der Proliferationsindices. Einen Anstieg der Proliferationsparameter unter der Therapie mit Pegvisomant fand sich dagegen nicht. Bei der Untersuchung von Tumorproben der im Intervall mehrfach operierten Patienten konnte im Einzelfall eine Änderung der Proliferationsindices unter veränderter medikamentöser oder strahlen-therapeutischer Therapie nachgewiesen werden. Es fand sich aber auch hier keine Zunahme der individuellen Proliferationsaktivität unter der Therapie mit Pegvisomant. Es bestätigten sich die teilweise in der Literatur beschriebenen Effekte der Behandlung mit Somatostatin-Analoga bei Patienten mit einer klinisch floriden Akromegalie und einem Wachstumshormon-sezernierenden Hypophysenadenom. Interessanterweise scheinen die proliferations-hemmenden Effekte der Therapie mit Somatostatin-Analoga auch nach deren Beendigung fortzubestehen. Eine Erhöhung der Proliferationsaktivität durch den Einsatz von Pegvisomant, ließ sich anhand der vorliegenden Daten aus der zulassungsgerechten klinischen Anwendung dieser Substanz nicht nachvollziehen. Der bisher unbekannte und erstmalig nachgewiesene, von der Dosis und Dauer abhängige Effekt einer Therapie mit Pegvisomant auf die Expression von Topoisomerase-IIα bedarf weiterer klinischer und experimenteller Untersuchungen.Untreated acromegaly is associated with a shortened life expectancy. Therefore, the goal of any therapy is normalization of growth hormone secretion. In addition to the causal, surgical treatment by resection of the growth hormone-producing tumour tissue, different drugs are available for medical treatment. The purpose of this study was to compare the influence of the last applied drug or radiotherapy on the immunhistochemical expression of the proliferation markers Ki-67 and topoisomerase-IIα in patients with growth hormone-secreting pituitary adenomas. Previously untreated tumours were compared with medically pretreated or irradiated ones. Of particular interest was the influence of the growth hormone receptor antagonist Pegvisomant. In some cases a significant tumour progression occurred during Pegvisomant therapy and in one patient an increase of the above mentioned proliferation parameters was reported. This effect has been assigned to the mechanism of action of the drug itself. A total of 385 formalin-fixed tumour samples from 368 patients, operated in the years between 2002 and 2010 were available for retrospective analysis. Each tumour sample was stained for the proliferation markers topoisomerase-IIα and Ki-67 and the proliferation was determined microscopically by counting positively stained cells. These results were correlated with clinical parameters and the nature, duration and dosage of the last applied drug. Basically, the proliferation parameters studied behaved congruent to each other. There were statistically significantly increased proliferation rates in larger and invasive adenomas or younger patients. The administration of dopamine agonists and somatostatin analogues resulted in a reduction of both proliferation parameters, whereas neither the duration of treatment nor the dosage of the drugs showed a definite influence. Only octreotide led in the group of densely-granulated pituitary adenomas to a statistically significant reduction in the proliferation indices. An increase of proliferation parameters in patients treated with Pegvisomant was not detectable. In addition, investigations of tumour samples of repeatedly operated patients who had been exposed to different drugs or radiation therapy occasionally led to a change of the proliferation indices, but an increase of proliferation during Pegvisomant treatment was never observed. This study confirmed some of the published effects of treatment with somatostatin analogues in patients with acromegaly and a growth hormone-secreting pituitary adenoma. Interestingly, the antiproliferative effects of a therapy with somatostatin analogues continued even after cessation of the application. An increase in the proliferative activity caused by the currently recommended clinical application of Pegvisomant was to not detected. The up to date unknown and herein demonstrated dose and duration-dependent effect of treatment with Pegvisomant on the expression of topoisomerase-IIα warrants further clinical and experimental studies

Novel Techniques in the Surgical Treatment of Acromegaly: Applications and Efficacy

Since the establishment of transsphenoidal microsurgery as the operative treatment of choice in most patients with acromegaly 40 years ago, a few novel technical developments have evolved. Their application, utility and efficacy will be briefly discussed in this review article, based on an analysis of published results and the authors' personal experience. The endoscope was additionally used to search for residual tumours in locations which could not be visualised with the operating microscope. In many centres it has by now fully replaced the operating microscope. Extended endoscopic operations hardly have limits in respect to accessible pathology. Overall, the results and complications reported from microsurgical and endoscopic series are comparable. Intraoperative magnetic resonance imaging allows depicting the completeness of a tumour resection. While in many patients additional tumour resections are performed on the basis of intraoperative imaging, the improvements in hormonal remission rates reported are less impressive. Neuronavigation uses imaging data to improve the surgeon's orientation, and it is certainly a major asset to the inexperienced. In high-caseload centres it is mainly appreciated in anatomical variants and reoperations. While the Doppler probe is a valuable and easily affordable gadget to avoid vascular arterial injury, intraoperative ultrasound imaging of tumour extension has a much poorer resolution than magnetic resonance imaging and is thus not widely implemented. The clinical value of intraoperative growth hormone measurements is controversially discussed. In summary, the application of modern technology has only led to a minor improvement of results, but it has widened the spectrum of accessible pathologies and increased the safety of the procedures for the patient. It is expected that outcomes will continue to improve as novel techniques and concepts are being developed

Surgical treatment of aggressive pituitary adenomas and pituitary carcinomas

Surgery of aggressive pituitary adenomas and pituitary carcinomas is part of the interdisciplinary management of these difficult to treat tumors. Invasion, giant size and unusual, asymmetric extent of these tumors frequently require modifications or extensions of the standard approaches for transsphenoidal and transcranial surgery. Frequently, only debulking procedures can be performed. In aggressive and hormone secreting adenomas, the remission rates achieved by surgery alone are relatively poor and adjuvant medical treatments or irradiation are needed. Safe resection of as much tumor as possible and symptomatic control is aimed at, rather than remission. Many procedures are required for rapid progression of lesions or recurrences, in order to extend the survival of the patients. Metastases of pituitary carcinomas within the cranial cavity or spine can be attacked. Since they can occur anywhere in the brain or spinal canal they require the entire battery of neurosurgical approaches. Unfortunately, in this group of pituitary tumors, the complication rates are higher than in primary operations of enclosed adenomas. The respective techniques with their facilities and limitations are reviewed in this article

Improved Detection of Cavernous Sinus Invasion of Pituitary Macroadenomas with Ultra-High-Field 7 T MRI

To compare 7 T magnetic resonance imaging (MRI) of pituitary macroadenomas (PMA) with standard MRI and intraoperative findings regarding tumor detection, localization, size, and extension. Patients with suspected pituitary adenoma underwent pre-operative 1.5 T or 3 T and 7 T MRI; 14 patients with a PMA were included. A qualitative (lesion detection, location, cavernous sinus infiltration) and quantitative (lesion size, depth of cavernous sinus infiltration) analysis of 1.5 T, 3 T and 7 T MRI was performed and compared with intraoperative findings. Both 1.5/3 T and 7 T MRI enabled the detection of all PMAs; lesion size determination was equal. 7 T MRI enables more precise assessments of cavernous sinus infiltration of PMA (ncorrect 7T = 78.6%, ncorrect 1.5/3T = 64.3%). Ultra-high-field MRI is a reliable imaging modality for evaluation of PMAs providing exact information on lesion location and size. 7 T MRI yielded more accurate information on cavernous sinus infiltration with better agreement with intraoperative findings than standard MRI

Rathke's Cleft Cyst as Origin of a Pediatric Papillary Craniopharyngioma

A 6-year old patient presented with an intra and suprasellar cystic lesion accompanied with impairment of the hypothalamic-pituitary axis and partial hypopituitarism. The most likely cause of sellar lesions in this age group are adamantinomatous craniopharyngioma (adaCP) or Rathke´s cleft cysts (RCCs). AdaCP are characterized by CTNNB1 mutations accompanied with aberrant nuclear beta-catenin expression. RCC show neither nuclear beta-catenin expression nor BRAF mutation. The latter is a hallmark of papillary craniopharyngiomas (papCP) that exhibit remarkable histological similarity with metaplasia of RCC. Diagnosis of the patient was elucidated by CTNNB1 and BRAF mutation screening, utilizing different approaches, as well as histological examination of markers, e.g., beta-catenin, claudin-1, EpCAM and the mutated BRAFV600E protein, which are known to be differentially expressed in sellar lesions. The case presented reveals extraordinary aspects for two reasons. Firstly, the lesion appeared clinically, on MRI, intraoperatively and histologically as RCC with prominent squamous metaplasia, but showing an expression pattern of markers also found in papCP, whilst exhibiting a hitherto undescribed BRAFV600E mutation. This important result documents a supposable transition of RCC metaplasia into a papillary craniopharyngioma (papCP). Secondly, this intriguing case shows unexpectedly that although papCP usually occurs almost exclusively in adults, it can also arise in childhood

Tight junction protein claudin-1 is differentially expressed in craniopharyngioma subtypes and indicates invasive tumor growth

Background: Claudins are tight junction proteins expressed in epithelial tissues that play important roles in cell polarity and adhesion. Altered distribution of claudin-1(CLDN1) affects cell mobility and tumor invasiveness. Craniopharyngiomas (CPs) represent epithelial tumors of the sellar region, consisting of adamantinomatous (adaCP) and papillary (papCP) variants. Their tendency to infiltrate surrounding brain structures complicates successful surgery. Reliable markers are required to predict tumor behavior and to establish individualized treatment protocols. Methods: We describe the distribution pattern of CLDN1 in a large cohort of 66 adaCPs, 21 papCPs, and 24 Rathke`s cleft cyst (RCC) cases using immunohistochemistry. CLDN1 mRNA levels were analyzed with qRT-PCR in 33 CP samples. The impact on the migration potential was studied in primary adaCP cell cultures (n = 11) treated with small interfering RNA (siRNA) for CLDN1. Furthermore, CLDN1 distribution patterns and expression levels were compared between invasive (n = 16) and noninvasive (n = 17) tumor groups. Results: PapCPs and RCCs exhibited a distinct homogenous and membranous expression pattern, whereas CLDN1 immunoreactivity appeared weaker and more heterogeneous in adaCPs. In the latter cases, whirl-like cell clusters showed complete absence of CLDN1. mRNA analysis confirmed reduced CLDN1 levels in adaCPs versus papCPs. Interestingly, invasive tumors exhibited significantly lower CLDN1 expression compared with noninvasive counterparts regardless of CP subtype. Accordingly, siRNA treatment for CLDN1 altered tumor cell migration in vitro. Conclusion: CLDN1 represents a novel marker in the differential diagnosis of CP variants and RCCs. Low CLDN1 expression levels correlate with an invasive CP growth pattern and may serve as a prognostic marker

Clinical Evaluation of an Innovative Metal-Artifact-Reduction Algorithm in FD-CT Angiography in Cerebral Aneurysms Treated by Endovascular Coiling or Surgical Clipping

Treated cerebral aneurysms (IA) require follow-up imaging to ensure occlusion. Metal artifacts complicate radiologic assessment. Our aim was to evaluate an innovative metal-artifact-reduction (iMAR) algorithm for flat-detector computed tomography angiography (FD-CTA) regarding image quality (IQ) and detection of aneurysm residua/reperfusion in comparison to 2D digital subtraction angiography (DSA). Patients with IAs treated by endovascular coiling or clipping underwent both FD-CTA and DSA. FD-CTA datasets were postprocessed with/without iMAR algorithm (MAR+/MAR−). Evaluation of all FD-CTA and DSA datasets regarding qualitative (IQ, MAR) and quantitative (coil package diameter/CPD) parameters was performed. Aneurysm occlusion was assessed for each dataset and compared to DSA findings. In total, 40 IAs were analyzed (ncoiling = 24; nclipping = 16). All iMAR+ datasets demonstrated significantly better IQ (pIQ coiling pIQ clipping aneurysm detection MAR+/MAR−/DSA = 22/1/26). The iMAR algorithm significantly improves IQ by effective reduction of metal artifacts in FD-CTA datasets. The proposed algorithm enables reliable detection of aneurysm residua/reperfusion with good agreement to DSA. Thus, iMAR can help to reduce the need for invasive follow-up in treated IAs

Case Report: Consecutive Adrenal Cushing’s Syndrome and Cushing’s Disease in a Patient With Somatic CTNNB1, USP8, and NR3C1 Mutations

The occurrence of different subtypes of endogenous Cushing’s syndrome (CS) in single individuals is extremely rare. We here present the case of a female patient who was successfully cured from adrenal CS 4 years before being diagnosed with Cushing’s disease (CD). The patient was diagnosed at the age of 50 with ACTH-independent CS and a left-sided adrenal adenoma, in January 2015. After adrenalectomy and histopathological confirmation of a cortisol-producing adrenocortical adenoma, biochemical hypercortisolism and clinical symptoms significantly improved. However, starting from 2018, the patient again developed signs and symptoms of recurrent CS. Subsequent biochemical and radiological workup suggested the presence of ACTH-dependent CS along with a pituitary microadenoma. The patient underwent successful transsphenoidal adenomectomy, and both postoperative adrenal insufficiency and histopathological workup confirmed the diagnosis of CD. Exome sequencing excluded a causative germline mutation but showed somatic mutations of the β-catenin protein gene (CTNNB1) in the adrenal adenoma, and of both the ubiquitin specific peptidase 8 (USP8) and the glucocorticoid receptor (NR3C1) genes in the pituitary adenoma. In conclusion, our case illustrates that both ACTH-independent and ACTH-dependent CS may develop in a single individual even without evidence for a common genetic background