Publications by authors named "Nelson Wohllk"

Medullary thyroid cancer (MTC) is a rare disease from parafollicular C cells. Calcitonin has been suggested as a screening; its levels are proportional to the tumor size and predictive of metastatic disease. We present a case where an early action was taken with lower cut-off points.

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Objective: Multiple endocrine neoplasia type 2A (MEN 2A) is a rare syndrome caused by RET germline mutations and has been associated with primary hyperparathyroidism (PHPT) in up to 30% of cases. Recommendations on RET screening in patients with apparently sporadic PHPT are unclear. We aimed to estimate the prevalence of cases presenting with PHPT as first manifestation among MEN 2A index cases and to characterize the former cases.

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Although most thyroid nodules with indeterminate cytology are benign, in most of the world, surgery remains as the most frequent diagnostic approach. We have previously reported a 10-gene thyroid genetic classifier, which accurately predicts benign thyroid nodules. The assay is a prototype diagnostic kit suitable for reference laboratory testing and could potentially avoid unnecessary diagnostic surgery in patients with indeterminate thyroid cytology.

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Background: Classification of growth hormone (GH) - secreting tumors by the granular pattern might predict their clinical behavior in acromegalic patients. There are several other prognostic factors.

Aim: To compare the features at presentation and cure rates of patients with GH secreting tumors according to the granular pattern, and to define independent prognostic factors for surgical treatment in these patients.

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Article Synopsis
  • - The study aims to investigate the long-term outcomes of patients with bilateral pheochromocytomas who underwent either total or cortical-sparing adrenalectomies, focusing on mortality risks, adrenal insufficiency, and tumor recurrence.
  • - Data from 625 patients treated between 1950 and 2018 revealed a significant presence of genetic mutations related to pheochromocytomas, with almost half of the patients experiencing adrenal insufficiency after total adrenalectomy, while complications were notably less in those who had cortical-sparing procedures.
  • - Of the 849 surgeries conducted, 52% were planned as cortical-sparing, with a success rate of 76.5%. The findings highlight the risks of long-term complications for patients post
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Background: Multiple endocrine neoplasia type 2B is a rare syndrome caused mainly by Met918Thr germline RET mutation, and characterised by medullary thyroid carcinoma, phaeochromocytoma, and extra-endocrine features. Data are scarce on the natural history of multiple endocrine neoplasia type 2B. We aimed to advance understanding of the phenotype and natural history of multiple endocrine neoplasia type 2B, to increase awareness and improve detection.

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Although the authors of the present review have contributed to genetic discoveries in the field of pheochromocytoma research, we can legitimately ask whether these advances have led to improvements in the diagnosis and management of patients with pheochromocytoma. The answer to this question is an emphatic ! In the field of molecular genetics, the well-established axiom that familial (genetic) pheochromocytoma represents 10% of all cases has been overturned, with >35% of cases now attributable to germline disease-causing mutations. Furthermore, genetic pheochromocytoma can now be grouped into five different clinical presentation types in the context of the ten known susceptibility genes for pheochromocytoma-associated syndromes.

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Pancreatic neuroendocrine tumors (PanNETs) are rare in von Hippel-Lindau disease (VHL) but cause serious morbidity and mortality. Management guidelines for VHL-PanNETs continue to be based on limited evidence, and survival data to guide surgical management are lacking. We established the European-American-Asian-VHL-PanNET-Registry to assess data for risks for metastases, survival and long-term outcomes to provide best management recommendations.

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Background: In most of the world, diagnostic surgery remains the most frequent approach for indeterminate thyroid cytology. Although several molecular tests are available for testing in centralized commercial laboratories in the United States, there are no available kits for local laboratory testing. The aim of this study was to develop a prototype in vitro diagnostic (IVD) gene classifier for the further characterization of nodules with an indeterminate thyroid cytology.

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Background: The prevention of medullary thyroid cancer in patients with multiple endocrine neoplasia type 2 syndrome has demonstrated the ability of molecular diagnosis and prophylactic surgery to improve patient outcomes. However, the other major neoplasia associated with multiple endocrine neoplasia type 2, phaeochromocytoma, is not as well characterised in terms of occurrence and treatment outcomes. In this study, we aimed to systematically characterise the outcomes of management of phaeochromocytoma associated with multiple endocrine neoplasia type 2.

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Background: Serum thyroglobulin (sTg) is an excellent marker of persistence or recurrence of disease in differentiated thyroid cancer (DTC), however its role as prognostic factor has not been fully established.

Aim: To assess the value of the preablative thyroglobulin (pTg) as predictor of disease-free survival in DTC.

Patients And Methods: Retrospective study of 104 patients with low and intermediate risk DTC subjected to total thyroidectomy and 131iodine ablation.

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Background: Dopamine agonists (DA) effectively reduce tumor size of macroprolactinomas, with the consequent improvement of eventual visual impairment.

Aim: To study the visual outcomes in patients with macroprolactinoma treated with DA.

Material And Methods: Retrospective cohort study which included patients with macroprolactinoma controlled at a Neuro-endocrinology and Neuro-ophthalmology Department between 1997 and 2011, and treated exclusively with DA (bromocriptine or cabergoline).

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Background: Adult hypothyroidism is a highly prevalent condition that impairs processes, such as learning and memory. Even though tetra-iodothyronine (T(4)) treatment can overcome the hypothyroidism in the majority of cases, it cannot fully recover the patient's learning capacity and memory. In this work, we analyzed the cellular and molecular changes in the adult brain occurring with the development of experimental hypothyroidism.

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Head and neck paragangliomas are tumors arising from specialized neural crest cells. Prominent locations are the carotid body along with the vagal, jugular, and tympanic glomus. Head and neck paragangliomas are slowly growing tumors, with some carotid body tumors being reported to exist for many years as a painless lateral mass on the neck.

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Multiple endocrine neoplasia (MEN) types 1 and 2 are genetic diseases that are inherited as autosomal traits. The major clinical manifestations of multiple endocrine neoplasia type 1 include the so-called "3 P's": parathyroid, pituitary, and pancreatic tumors, including gastroenteroneuroendocrine tumors. Genetic testing can be performed on patients and the potential carriers of the menin gene mutation, but the genotype-phenotype correlation in multiple endocrine neoplasia type 1 is less straightforward than multiple endocrine neoplasia type 2.

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Paragangliomas are tumors arising from sympathetic and parasympathetic tissues. The classic associated syndromes are neurofibromatosis type 1, multiple endocrine neoplasia type 2 and von Hippel-Lindau. Germline mutations of succinate dehydrogenase subunits genes, are associated with familial paraganglioma syndromes 1,2,3 and 4.

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Addisonian crisis as a first manifestation of metastatic disease secondary to cancer is uncommon. We report a 63-year-old man with a history of one year of fatigue, weakness, weight loss and repeated symptomatic hypoglycemia. The cortisol stimulation test with ACTH confirmed primary adrenal insufficiency.

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Article Synopsis
  • - Multiple endocrine neoplasia type 2 is linked to specific mutations in the RET gene, particularly in exon 10, with limited existing data on their effects.
  • - The International RET Exon 10 Consortium conducted a study with 340 subjects to analyze different clinical-risk profiles related to medullary thyroid carcinoma (MTC), pheochromocytoma, and hyperparathyroidism associated with these mutations.
  • - Findings revealed varying rates of disease presentation based on specific codon mutations, with a higher penetrance for MTC and a correlation between advanced disease stages and the position of mutations within the gene.
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Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant cancer syndrome with major components of medullary thyroid carcinoma (MTC), pheochromocytoma and hyperparathyroidism. The disease is caused by germline mutations of the RET proto-oncogene. Subtypes of MEN 2 include MEN 2A, MEN 2B and familial MTC (FMTC) which differ in pattern of additional lesions or--in FMTC--lack of pheochromocytoma.

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Several guidelines on diagnosis and treatment of thyroid nodules and cancer have recently been published. However, recommended practices are not always appropriate to different settings or countries. The aim of this consensus was to develop Clinical Guidelines for evaluation and management of patients with thyroid nodules applicable to Latin American countries.

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The aims of these recommendations were to develop clinical guidelines for evaluation and management of patients with differentiated thyroid cancer applicable to Latin American countries. The panel was composed by 13 members of the Latin American Thyroid Society (LATS) involved with research and management of thyroid cancer from different medical centers in Latin America. The recommendations were produced on the basis of the expert opinion of the panel with use of principles of Evidence-Based Medicine.

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Background: During the detection of neck recurrence in patients with Papillary Thyroid Carcinoma (PTC), sometimes it is difficult to distinguish metastatic from inflammatory neck lymph nodes. The measurement of serum thyroglobulin (sTg) under thyroid hormone suppression therapy the presence of serum thyroglobulin antibodies (sAbTg), the diagnostic whole body scan and cytology can give false negative results. Measurement of thyroglobulin in the washout fluid from fine-needle aspiration biopsy (FNAB) of suspicious neck lymph nodes could improve the diagnostic accuracy.

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