Donato Iacovazzo

Factors predicting pasireotide responsiveness in somatotroph pituitary adenomas resistant to first generation somatostatin analogues: an immunohistochemical study

AIM To gather data regarding factors predicting responsiveness to pasireotide in acromegaly. PATIENTS AND METHODS SSTR2a, SSTR3, SSTR5, AIP, Ki-67 and the adenoma subtype were evaluated in somatotroph adenomas from 39 patients treated post-operatively with somatostatin analogues (SSAs). A standardized SSTR scoring system was applied (scores 0-3). All patients received first-generation SSAs, and 11 resistant patients were subsequently treated with pasireotide LAR. RESULTS None of the patients with negative or cytoplasmic-only SSTR2a expression (scores 0-1) were responsive to first-generation SSAs, as opposed to 20% (score 2) and 50% of patients with a score of 3 (P=0.04). None of the patients with an SSTR5 score of 0-1 were responsive to pasireotide, as opposed to 5/7 cases with a score of 2 or 3 (P=0.02). SSTR3 expression did not influence first-generation SSAs or pasireotide responsiveness. Tumours with low AIP were resistant to first-generation SSAs (100 vs 60%; P=0.02), while they had similar responsiveness to pasireotide compared to tumours with conserved AIP expression (50 vs 40%; P=0.74). Tumours with low AIP displayed reduced SSTR2 (SSTR2a scores 0-1 44.4 vs 6.7%; P=0.006) while no difference was seen in SSTR5 (SSTR5 scores 0-1 33.3 vs 23.3%; P=0.55). Sparsely granulated adenomas responded better to pasireotide compared to densely granulated ones (80 vs 16.7%; P=0.04). CONCLUSION The expression of SSTR5 might predict responsiveness to pasireotide in acromegaly. AIP deficient and sparsely granulated adenomas may benefit from pasireotide treatment. These results need to be confirmed in larger series of pasireotide-treated patients.

Typical and Atypical Pituitary Adenomas: A Single-Center Analysis of Outcome and Prognosis

Background and Objective: In 2004, the World Health Organization defined atypical pituitary adenomas as those with a Ki-67 expression >3%, an excessive p53 expression and increased mitotic activity. As the usefulness of this classification is controversial, we reviewed typical and atypical pituitary adenomas to compare the clinical and prognostic features. Patients and Methods: We retrospectively reviewed 343 consecutive pituitary adenomas. Atypical pituitary adenomas represented 18.7% of cases. All patients were operated on at the Department of Neurosurgery of our institution and were followed up at the Hypothalamic-Pituitary Disease Unit of the same institution. The median follow-up time was 75 months (range 7-345). Results: Younger age at diagnosis as well as immunohistochemical positivity for adrenocorticotropic hormone and prolactin correlated with a higher risk of atypical pituitary adenomas, whereas typical and atypical pituitary adenomas did not differ with regard to gender, tumor size, recurrence risk and disease-free survival time (DFST). Among the 219 patients who underwent radical surgery, a Ki-67 expression ≥1.5% was associated with a higher risk of recurrence and a worse DFST, even after correction for age at diagnosis, gender, immunohistochemical classification, tumor size, invasiveness and Knosp classification [p = 0.01; hazard ratio (HR) 2.572; 95% confidence interval (CI) 1.251-5.285). Pituitary adenomas with a Ki-67 expression ≥1.5% showed a worse DFST as compared to pituitary adenomas with a Ki-67 expression <1.5% (HR 2.166; 95% CI 1.154-4.064). Conclusion: In this series, atypical and typical pituitary adenomas did not differ with regard to recurrence and DFST. Pituitary adenomas with a Ki-67 expression ≥1.5% showed a higher recurrence risk and a worse DFST as compared to those with a Ki-67 expression <1.5%. We suggest that a Ki-67 expression ≥1.5% may be useful as a prognostic marker, though this will need to be confirmed by prospective, multicenter data.

Somatic GPR101 Duplication Causing X-Linked Acrogigantism (XLAG)—Diagnosis and Management

Context: Recent reports have proposed that sporadic or familial germline Xq26.3 microduplications involving the GPR101 gene are associated with early-onset X-linked acrogigantism (XLAG) with a female preponderance. Case Description: A 4-year-old boy presented with rapid growth over the previous 2 years. He complained of sporadic headaches and had coarse facial features. His height Z-score was +4.89, and weight Z-score was +5.57. Laboratory testing revealed elevated serum prolactin (185 μg/L; normal, <18 μg/L), IGF-1 (745 μg/L; normal, 64–369 μg/L), and fasting GH > 35.0 μg/L. Magnetic resonance imaging demonstrated a homogenous bulky pituitary gland (18 × 15 × 13 mm) without obvious adenoma. A pituitary biopsy showed hyperplastic pituitary tissue with enlarged cords of GH and prolactin cells. Germline PRKAR1A, MEN1, AIP, DICER1, CDKN1B, and somatic GNAS mutations were negative. Medical management was challenging until institution of continuous sc infusion of short-acting octreotide combined with sc pegvisomant and oral cabergoline. The patient remains well controlled with minimal side effects 7 years after presentation. His phenotype suggested XLAG, but his peripheral leukocyte-, saliva-, and buccal cell-derived DNA tested negative for microduplication in Xq26.3 or GPR101. However, DNA isolated from the pituitary tissue and forearm skin showed duplicated dosage of GPR101, suggesting that he is mosaic for this genetic abnormality. Conclusions: Our patient is the first to be described with somatic microduplication leading to typical XLAG phenotype. This patient demonstrates that a negative test for Xq26.3 microduplication or GPR101 duplication on peripheral blood DNA does not exclude the diagnosis of XLAG because it can result from a mosaic mutation affecting the pituitary.

Duplication Causing X-Linked Acrogigantism (XLAG) - Diagnosis and Management

Context: Recent reports have proposed that sporadic or familial germline Xq26.3 microduplications involving the GPR101 gene are associated with early-onset X-linked acrogigantism (XLAG) with a female preponderance. Case Description: A 4-year-old boy presented with rapid growth over the previous 2 years. He complained of sporadic headaches and had coarse facial features. His height Z-score was +4.89, and weight Z-score was +5.57. Laboratory testing revealed elevated serum prolactin (185 μg/L; normal, <18 μg/L), IGF-1 (745 μg/L; normal, 64–369 μg/L), and fasting GH > 35.0 μg/L. Magnetic resonance imaging demonstrated a homogenous bulky pituitary gland (18 × 15 × 13 mm) without obvious adenoma. A pituitary biopsy showed hyperplastic pituitary tissue with enlarged cords of GH and prolactin cells. Germline PRKAR1A, MEN1, AIP, DICER1, CDKN1B, and somatic GNAS mutations were negative. Medical management was challenging until institution of continuous sc infusion of short-acting octreotide combined with sc pegvisomant and oral cabergoline. The patient remains well controlled with minimal side effects 7 years after presentation. His phenotype suggested XLAG, but his peripheral leukocyte-, saliva-, and buccal cell-derived DNA tested negative for microduplication in Xq26.3 or GPR101. However, DNA isolated from the pituitary tissue and forearm skin showed duplicated dosage of GPR101, suggesting that he is mosaic for this genetic abnormality. Conclusions: Our patient is the first to be described with somatic microduplication leading to typical XLAG phenotype. This patient demonstrates that a negative test for Xq26.3 microduplication or GPR101 duplication on peripheral blood DNA does not exclude the diagnosis of XLAG because it can result from a mosaic mutation affecting the pituitary.

Evaluation of the Added Value of Diffusion-Weighted Imaging to Conventional Magnetic Resonance Imaging in Pancreatic Neuroendocrine Tumors and Comparison With 68Ga-DOTANOC Positron Emission Tomography/Computed Tomography.

Objectives The aims of this study were to investigate the added value of diffusion-weighted imaging (DWI) in pancreatic neuroendocrine tumor (pNET) evaluation and to compare magnetic resonance imaging (MRI) to 68Ga-DOTANOC positron emission tomography/computed tomography (PET/CT) results. Methods Morphological MRI (T2-weighted [T2-w] + contrast-enhanced [CE] T1-w) and DWI (T2-w + DWI) and 68Ga-DOTANOC PET/CT in 25 patients/30 pNETs were retrospectively evaluated. Per-patient and per-lesion detection rates (pDR and lDR, respectively) were calculated. Apparent diffusion coefficient values were compared among pNET and surrounding and normal pancreas (control group, 18 patients). Apparent diffusion coefficient and standardized uptake value (SUV) values were compared among different grading and staging groups. Results No statistically significant differences in PET/CT and MRI session detection rates were found (morphological MRI and DW-MRI, 88% pDR and 87% lDR; combined evaluation, 92% pDR and 90% lDR; 68Ga-DOTANOC PET/CT, 88% pDR and 80% lDR). Consensus reading (morphological/DW-MRI + PET/CT) improved pDR and lDR (100%). Apparent diffusion coefficient mean value was significantly lower compared with surrounding and normal parenchyma (P < 0.01). The apparent diffusion coefficient and SUV values of pNETs among different grading and staging groups were not statistically different. Conclusions Conventional MRI, DW-MRI + T2-w sequences, and 68Ga-DOTANOC PET/CT can be alternative tools in pNET detection. Diffusion-weighted MRI could be valuable in patients with clinical suspicion but negative conventional imaging findings. However, the consensus reading of the 3 techniques seems the best approach.

SDHA mutated paragangliomas may be at high risk of metastasis

We report the clinical outcomes of eleven patients with succinate dehydrogenase subunit A (SDHA) germline mutations from three UK tertiary referral centres to highlight a more diverse and expanding clinical spectrum of associated phenotypes. We suggest that SDHA paraganglioma-related disease is not a low-risk condition as first described. Of our six index cases, two developed metastatic disease and a further one had local vascular invasion. One patient developed multiple metachronous disease. Therefore, we believe these patients, like those with SDHB and SDHD mutations, should be part of a surveillance programme. Paraganglioma (PGL)-associated mutations in SDHA have only been reported in a small number of patients worldwide. There is controversy over the necessity for surveillance screening in these patients, compared to SDHB and SDHD, as penetrance is thought to be lower (Benn et al. 2015) and variants exist with uncertain pathogenicity. Initial reports associated SDHA with autosomal recessive causes of juvenile encephalopathy (Leigh syndrome) (Bourgeron et al. 1995) and homozygous mutations in SDHA cause severe neurological dysfunction and cardiomyopathy (Renkema et al. 2015). SDHA mutations have now been associated with phaeochromocytoma and paraganglioma (PPGL) formation in an autosomal dominant manner. SDHA mutations account for only 3% of cases of familial PGL cases, with presumed low penetrance (Korpershoek et al. 2011) and therefore very little data on clinical features of SDHA-related PPGL exist. Six index cases were originally diagnosed between 1973 and 2011 and had histologically proven PPGL, who subsequently underwent genetic testing during the course of their follow-up and were confirmed to have an underlying SDHA germline mutation. We performed a retrospective analysis of their notes and describe their clinical outcomes. From these six index cases, cascade genetic testing occurred and identified five further asymptomatic carriers of SDHA mutations. All patients are now being followed up in specialised endocrine clinics and are undergoing annual screening, including annual clinical and biochemical assessment and cross-sectional imaging, although the frequency and modality of imaging differs between centres. To predict the pathogenicity of the DNA variants, the missense variants were investigated in silico using PloyPhen2 and SIFT. Table 1 provides a detailed summary of the patients described. The six index patients originally presented were aged 18, 34, 36, 46, 47 and 68 years. Five patients presented with a single lesion at diagnosis: intrathyroidal PGL, mediastinal PGL, phaeochromocytoma and two extraadrenal PGLs. One patient (patient 3) presented with two synchronous lesions: she had a 3-methoxytyramine (3MT)-secreting carotid body tumour and a noradrenalinesecreting thoracic PGL. All patients underwent surgical resection of the primary tumours. Two patients developed recurrence in the surgical bed and both patients went on to develop metastatic disease 16 and 37 years later (patients 8 and 9). One of these two patients (patient 8) also developed an additional five metachronous lesions 7–10 years after original diagnosis. These two cases are described in more detail. Patient 8 presented aged 46 years with headaches and malignant hypertension (210/130 mmHg). Urinary noradrenaline was very raised (Table 1) and imaging confirmed a 5 cm para-adrenal PGL, which was subsequently resected. He developed a symptomatic recurrence one year later, which was surgically resected. Eight years after his original diagnosis, he presented with symptoms of catecholamine excess and four new lesions were identified and resected. On surveillance imaging three years later, a new non-secretory lesion was identified. Surgical resection was undertaken one year subsequently due to increasing PGL size and plasma catecholamine levels. He remained well with no evidence of further disease on imaging until five years later when rising noradrenaline levels were noted and uptake in the left adrenal bed and in the vertebral body of L4 was

PRKAR1A mutation causing pituitary-dependent Cushing disease in a patient with Carney complex

CONTEXT Carney complex (CNC) is an autosomal dominant condition caused, in most cases, by an inactivating mutation of the PRKAR1A gene, which encodes for the type 1 alpha regulatory subunit of protein kinase A. CNC is characterized by the occurrence of endocrine overactivity, myxomas and typical skin manifestations. Cushing syndrome due to primary pigmented nodular adrenocortical disease (PPNAD) is the most frequent endocrine disease observed in CNC. CASE DESCRIPTION Here, we describe the first case of a patient with CNC and adrenocorticotropic hormone (ACTH)-dependent Cushing disease due to a pituitary corticotroph adenoma. Loss-of-heterozygosity analysis of the pituitary tumour revealed loss of the wild-type copy of PRKAR1A, suggesting a role of this gene in the pituitary adenoma development. CONCLUSION PRKAR1A loss-of-function mutations can rarely lead to ACTH-secreting pituitary adenomas in CNC patients. Pituitary-dependent disease should be considered in the differential diagnosis of Cushing syndrome in CNC patients.

In-frame seven amino-acid duplication in AIP arose over the last 3000 years, disrupts protein interaction and stability and is associated with gigantism.

Objective Mutations in the aryl hydrocarbon receptor-interacting protein (AIP) gene are associated with pituitary adenoma, acromegaly and gigantism. Identical alleles in unrelated pedigrees could be inherited from a common ancestor or result from recurrent mutation events. Design and methods Observational, inferential and experimental study, including: AIP mutation testing; reconstruction of 14 AIP-region (8.3 Mbp) haplotypes; coalescent-based approximate Bayesian estimation of the time to most recent common ancestor (tMRCA) of the derived allele; forward population simulations to estimate current number of allele carriers; proposal of mutation mechanism; protein structure predictions; co-immunoprecipitation and cycloheximide chase experiments. Results Nine European-origin, unrelated c.805_825dup-positive pedigrees (four familial, five sporadic from the UK, USA and France) included 16 affected (nine gigantism/four acromegaly/two non-functioning pituitary adenoma patients and one prospectively diagnosed acromegaly patient) and nine unaffected carriers. All pedigrees shared a 2.79 Mbp haploblock around AIP with additional haploblocks privately shared between subsets of the pedigrees, indicating the existence of an evolutionarily recent common ancestor, the ‘English founder’, with an estimated median tMRCA of 47 generations (corresponding to 1175 years) with a confidence interval (9–113 generations, equivalent to 225–2825 years). The mutation occurred in a small tandem repeat region predisposed to slipped strand mispairing. The resulting seven amino-acid duplication disrupts interaction with HSP90 and leads to a marked reduction in protein stability. Conclusions The c.805_825dup allele, originating from a common ancestor, associates with a severe clinical phenotype and a high frequency of gigantism. The mutation is likely to be the result of slipped strand mispairing and affects protein–protein interactions and AIP protein stability.

Gigantism: X-linked acrogigantism and GPR101 mutations.

X-linked acrogigantism (XLAG) is a recently identified condition of early-onset GH excess resulting from the germline or somatic duplication of the GPR101 gene on chromosome Xq26.3. Thirty patients have been formally reported so far. The disease affects mostly females, occurs usually sporadically, and is characterised by early onset and marked overgrowth. Most patients present with concomitant hyperprolactinaemia. Histopathology shows pituitary hyperplasia or pituitary adenoma with or without associated hyperplasia. XLAG-related pituitary adenomas present peculiar histopathological features that should contribute to raise the suspicion of this rare condition. Treatment is frequently challenging and multi-modal. While females present with germline mutations, the sporadic male patients reported so far were somatic mosaics with variable levels of mosaicism, although no differences in the clinical phenotype were observed between patients with germline or somatic duplication. The GPR101 gene encodes an orphan G protein-coupled receptor normally expressed in the central nervous system, and at particularly high levels in the hypothalamus. While the physiological function and the endogenous ligand of GPR101 are unknown, the high expression of GPR101 in the arcuate nucleus and the occurrence of increased circulating GHRH levels in some patients with XLAG, suggest that increased hypothalamic GHRH secretion could play a role in the pathogenesis of this condition. In this review, we summarise the published evidence on XLAG and GPR101 and discuss the results of recent studies that have investigated the potential role of GPR101 variants in the pathogenesis of pituitary adenomas.

Treatment of hyperprolactinemia in post-menopausal women: pros

The incidence of hyperprolactinemia in women peaks during the 3rd–4th decade and then greatly decreases after the menopause. Apart from the effects on the hypothalamic–pituitary–gonadal axis, prolactin can act directly on bone metabolism. Hyperprolactinemia is a recognized cause of secondary osteoporosis, and treatment with dopamine agonists can lead to improved BMD. Moreover, hyperprolactinemia has been linked to weight gain and insulin resistance, which can be ameliorated following medical treatment. Although relatively rare, prolactinomas can be observed in post-menopausal women and are frequently large and invasive; dopamine agonists appear to be as effective in these patients as in younger women to induce reduction of prolactin levels and tumour shrinkage. Here, we review data potentially favouring medical treatment with dopamine agonists in post-menopausal women diagnosed with hyperprolactinemia.