Detection of RAS mutation by pyrosequencing in thyroid cytology samples

Genetic differences in follicular thyroid carcinoma between Asian and Western countries: a systematic review

Thyroid cancer is the most common endocrine malignancy, and follicular thyroid carcinoma (FTC) is the second most common thyroid cancer following papillary thyroid carcinoma (PTC). RAS mutation and PAX8/PPARγ rearrangement are the two representative genetic alterations in FTC, and there are studies from various countries on their regional frequencies. In this study, we systematically reviewed all available literature aiming to create a complete global map showing the frequencies of these common oncogenic drivers in FTC and to highlight the trends in Asian and Western countries. We performed a search in two electronic databases and identified 71 studies that fit our criteria from 1,329 studies found with our database search terms. There were 54 articles with 1,143 FTC patients and 39 articles with 764 FTC patients available for calculating the frequency of RAS mutation and PAX8/PPARγ rearrangement, respectively. NRAS mutation was the most frequent RAS mutation in all regions, followed by HRAS and KRAS mutation. The frequency of RAS mutation in Asian countries was higher than Western countries (34% vs. 27%, P=0.006) when the mutation detection method was not taken into account. In contrast, this difference in RAS mutation incidence between Asian and Western countries (28% vs. 25%, P=0.47) did not show up in our subgroup analysis incorporating only studies using direct sequencing method. The reported difference of RAS mutation frequency in the previous literature might not be due to the true prevalence of RAS mutation. They could be attributed to the difference in the detection method. As to PAX8/PPARγ rearrangement, Western countries overall had a much higher prevalence than Asian countries (23% vs. 4%, P<0.001), but some European countries had a low incidence, implying regional heterogeneity of PAX8/PPARγ rearrangement. A substantial lack of mutation data in FTC was found in several regions of the world such as Central Asia, Middle East, Africa, and Central and South America. Our results provide the most comprehensive global status of representative genetic alterations in FTC and highlight the similarities and differences between Asian and Western countries.

Identification of Tissue-Specific DNA Methylation Signatures for Thyroid Nodule Diagnostics

PURPOSE

Thyroid cancer is frequently difficult to diagnose due to an overlap of cytologic features between malignant and benign nodules. This overlap leads to unnecessary removal of the thyroid in patients without cancer. While providing some improvement over cytopathologic diagnostics, molecular methods frequently fail to provide a correct diagnosis for thyroid nodules. These approaches are based on the difference between cancer and adjacent thyroid tissue and assume that adjacent tissues are the same as benign nodules. However, in contrast to adjacent tissues, benign thyroid nodules can contain genetic alterations that can be found in cancer.Experimental Design: For the development of a new molecular diagnostic test for thyroid cancer, we evaluated DNA methylation in 109 thyroid tissues by using genome-wide single-base resolution DNA methylation analysis. The test was validated in a retrospective cohort containing 65 thyroid nodules.

RESULTS

By conducting reduced representation bisulfite sequencing in 109 thyroid specimens, we found significant differences between adjacent tissue, benign nodules, and cancer. These tissue-specific signatures are strongly linked to active enhancers and cancer-associated genes. Based on these signatures, we developed a new epigenetic approach for thyroid diagnostics. According to the validation cohort, our test has an estimated specificity of 97% [95% confidence interval (CI), 81-100], sensitivity of 100% (95% CI, 87-100), positive predictive value of 97% (95% CI, 83-100), and negative predictive value of 100% (95% CI, 86-100).

CONCLUSIONS

These data show that epigenetic testing can provide outstanding diagnostic accuracy for thyroid nodules.See related commentary by Mitmaker et al., p. 457.

Surgical approach in thymectomy: Our experience and review of the literature

Aim

Thymectomy is the main treatment for thymoma and patients with myasthenia gravis (MG). The traditional approach is through a median sternotomy, but, recently, thymectomy through minimally invasive approaches is increasingly performed. Our purpose is an analysis and discussion of the clinical presentation, the diagnostic procedures and the surgical technique. We also consider post-operative complications and results, over a period of 5 years (May 2011–June 2016), in thymic masses admitted in our Thoracic Surgery Unit.

Methods

We analyzed 8 patients who underwent surgical treatment for thymic masses over a period of 5 years. 6 patients (75%) had thymoma, 2 patients (25%) had thymic carcinomas. 2 patients with thymoma (33%) had myasthenia gravis. We performed a complete surgical resection with median sternotomy as standard approach.

Results

One patient (12%) died in the postoperative period. The histological study revealed 6 (75%) thymoma and 2 (25%) thymic carcinomas. Post-operative morbidity occurred in 2 patients (25%) and were: pneumonia in 1 case (12%), atrial fibrillation and pleural effusion in 2 patients (25%). One patient with thymoma type A recurred at skeletal muscle 2-years after surgery.

Conclusions

Thymic malignancies are rare tumors. Surgical resection is the main treatment, but a multimodal approach is useful for many patients. Radical thymectomy is completed removing all the soft tissue in the anterior mediastinum between the two phrenic nerves and this is the most important factor in controlling myasthenia and influencing survival in patients with thymoma. Open (median sternotomy) approach has been the standard approach for thymectomy for the better visualization of the anatomical structures. Actually, video-assisted thoracoscopic surgery (VATS) thymectomy and robotic video-assisted thoracoscopic (R-VATS) approach versus open surgery has an equal if not superior oncological efficacy, better perioperative complications and survival outcomes.

Idiopathic pleural panniculitis with recurrent pleural effusion not associated with Weber-Christian disease

A 82-year-old patient with dyspnea and a recurrent history of pleural effusion was admitted into our unit. He performed a Chest computed tomography showing right pleural effusion. Video-assisted thoracoscopy (VATS) exploratory showed parietal pleural thickening of adipose tissue. The surgical procedure consisted, therefore, in the execution of multiple biopsies of the parietal pleura which appeared covered, on the whole surface, by islands of adipose tissue, without macroscopic pathological aspects. After the procedure was performed pleurodesis with talc. The definitive histological examination consisted of normal mesothelial cells surrounded by fatty tissue infiltrated by small lymphocytes in a patient without skin lesions or visceral or systemic signs of inflammatory involvement of the adipose tissue. We reported a rare case of idiopathic pleural panniculitis with recurrent pleural effusion not associated with Weber-Christian disease.

Diagnostic Value of RAS Mutations in Indeterminate Thyroid Nodules

Objectives To determine the diagnostic value of HRAS, KRAS, and NRAS mutations in fine-needle aspiration biopsies of thyroid nodules that are nondiagnostic on cytology. Data Sources PubMed, Scopus, Embase, CINAHL. Review Methods Two authors independently searched the data sources. To be included, studies reported the RAS mutational status and postoperative histopathologic diagnosis of nodules that exhibited indeterminate cytology after fine-needle aspiration biopsy. Data were extracted to calculate sensitivity, specificity, and positive/negative predictive values of any HRAS, KRAS, or NRAS mutation. A meta-analysis was performed to generate pooled values for each parameter. Results A total of 7 studies with a combined 1025 patients met inclusion criteria. The pooled sensitivity of a RAS mutation for detecting cancer was 0.343 (95% confidence interval [95% CI], 0.198-0.506), while the pooled specificity was 0.935 (95% CI, 0.882-0.973). The weighted averages for positive predictive value and negative predictive value were 78.0% and 64.0%, respectively, with 68.0% accuracy. The positive likelihood ratio was 4.235 (95% CI, 1.506-11.910), and the negative likelihood ratio was 0.775 (95% CI, 0.630-0.953). Conclusion Our data suggest that testing for any RAS mutation is unlikely to change the clinical management of thyroid nodules that have indeterminate cytology. While a RAS mutation may rule in malignancy, the sensitivity of testing is low enough to merit further mutational analysis, repeat fine-needle aspiration, or surgical excision, even in the presence of a negative test.

RAS Mutations, and RET/PTC and PAX8/PPAR-gamma Chromosomal Rearrangements Are Also Prevalent in Benign Thyroid Lesions: Implications Thereof and A Systematic Review

BACKGROUND

Molecular markers associated with thyroid malignancy are increasingly being used as differential diagnostic tools for thyroid nodules. However, little has been reported recently regarding the prevalence of these markers in benign lesions. The literature was systematically reviewed to examine studies that reported on the prevalence of these markers in benign thyroid lesions.

METHODS

Appropriate studies published between January 1, 2000, and April 30, 2015, and cataloged in PubMed, Embase, Cochrane, Scopus, and Web of Science databases were searched for by combining different keywords for "thyroid tumor" with both general and specific keywords for "molecular marker" by using "AND" as the Boolean operator. All studies meeting criteria that reported the prevalence of RAS mutations, and RET/PTC and PAX8/PPAR-gamma chromosomal rearrangements in benign thyroid lesions were included for study.

RESULTS

A total of 64 articles (including 8162 patients, of whom 42.5% had benign lesions) that met all the study criteria were systematically reviewed and abstracted. Among 35 studies examining RAS mutations, the reported prevalence of RAS mutation in benign lesions ranged from 0% to 48%. In 38 studies examining RET/PTC rearrangements, the prevalence in benign lesions ranged from 0% to 68%. PAX8/PPAR-gamma rearrangements were examined in 27 studies, with the prevalence in benign lesions ranging from 0% to 55%.

CONCLUSION

The presence of these biomarkers and the tremendous variation in reports of their prevalence in benign lesions suggests the need for caution when including these markers in diagnostic decisions. Further understanding of the importance of these markers, as well as newly discovered markers of thyroid malignancy, may be required in order to avoid overtreatment of patients with benign thyroid tumors.

Benign thyroid nodules with RAS mutation grow faster

CONTEXT

The management of a benign thyroid nodule includes follow-up until its size requires a surgical or alternative treatment. To date, it is difficult or impossible to predict the size changes of a benign nodule in a given patient because no specific growth parameters exist. RAS mutations have been described in thyroid adenomas and hyperplastic benign nodules.

OBJECTIVE

The aim of this study was to establish whether the volume changes of benign nodules are associated with the presence of RAS mutation.

PATIENTS AND METHODS

Genomic DNA obtained by fine-needle aspiration of 78 thyroid nodules with benign cytology was analysed by pyrosequencing for the presence of NRAS(61) and KRAS(13) mutations. Ultrasonographic features were obtained. The volume of nodules at baseline and their changes after a mean follow-up of 25 months were evaluated according to the presence of RAS mutation.

RESULTS

A RAS mutation was found in 24 thyroid aspirates (30·8%, 8 NRAS(61) and 16 KRAS(13) ). RAS mutation was not associated with ultrasonographic features, but was significantly associated with a larger size at baseline (P = 0·017). After a 25-month mean follow-up, RAS mutation-positive nodules displayed faster growth (RAS mutation-positive vs RAS mutation-negative % annual growth 27·6% ±32·2% vs 1·0% ±17·0%, P < 0·001).

CONCLUSIONS

Benign thyroid nodules bearing RAS mutation grow more rapidly than those with wild-type RAS. Searching for RAS mutations in thyroid nodules with benign cytology might be useful to the clinician in choosing a more appropriate and timely surgical management.

Cushing's like syndrome in typical bronchial carcinoid a case report and review of the literature

Cushing’s syndrome occurred in 1–5% of cases of bronchial carcinoids. In this paper we describe a case of typical bronchial carcinoid in a nonsmoker young male with clinical manifestations mimicking a Cushing’s syndrome. The patient performed chest radiograph and computed tomography. Fiberoptic bronchoscopy revealed the presence of an endobronchial mass occluding the bronchus intermedius. A rigid bronchoscopy was necessary for the conclusive diagnosis and for partial resection of the intraluminal tumor. Despite of the presence of Cushingoid features, the normal blood levels of ACTH and cortisol excluded the coexistence of a Cushing’s syndrome.

Surgical management of cervico-mediastinal goiters: Our experience and review of the literature

AIM

We analyze and discuss the clinical presentation, the diagnostic procedures and the surgical technique in relation to post-operative complications and results in cervico-mediastinal thyroid masses admitted in Thoracic Surgery Unit of AOU Second University of Naples from 1991 to 2006 and in Thoracic Surgery Unit of AOU "S. Giovanni di Dio & Ruggi D'Aragona" of Salerno over a period of 3 years (2011-2014).

METHODS

We reviewed 97 patients who underwent surgical treatment for cervico-mediastinal goiters. 47 patients (49.2%) had cervico-mediastinal goiter, 40 patients (40%) had mediastino-cervical goiter and 10 patients (10.8%) had mediastinal goiter. 73 cases were prevascular goiters and 24 were retrovascular goiters. We performed total thyroidectomy in 40 patients, subtotal thyroidectomy in 46 patients and in 11 cases the resection of residual goiter. In 75 patients we used only a cervical approach, in 21 patients the cervical incision was combined with median sternotomy and in 1 patient with transverse sternotomy.

RESULTS

Three patients (3.1%) died in the postoperative period (2 cardio-respiratory failure and 1 pulmonary embolism). The histologic study revelead 8 (7.7%) carcinomas. Postoperative complications were: dyspnea in 9 cases (10.7%), transient vocal cord paralysis in 6 patients (9.2%), temporary hypoparathyroidism in 9 patients (9.2%) and kidney failure in 1 case (0.9%).

CONCLUSIONS

The presence of a cervico-mediastinal thyroid mass with or without respiratory distress requires a surgical excision as the only treatment option. Thyroid masses extending to the mediastinum can be excised successfully by cervical incision. Bipolar approach (cervical incision and sternotomy) has an excellent outcome, achieving a safe resection, especially in large thyroid masses extending to the mediastinum with close relations to mediastinal structures and in some limited cases (carcinoma, thyroiditis, retrovascular goiter, ectopic goiter). Postoperative mortality and morbidity is very low, independent of surgical techniques. Other surgical approaches for excision of a Posterior Mediastinal Thyroid Goiter reported in literature are: VATS techniques to remove an ectopic intrathoracic goiter, robot-assisted technique for the removal of a substernal thyroid goiter, with extension into the posterior mediastinum.

Pulmonary arterovenous malformation causing hemothorax in a pregnant woman without Osler-Weber-Rendu syndrome

Pulmonary arteriovenous malformations (PAVMs), although most commonly congenital, are usually detected later in life. Case report: We present a case of a 19-year-old woman with no previous history of AVM or telangiectasia, who presented dyspnea and hypoxia by massive left hemothorax in the 34th week of gestation. After emergent cesarean delivery, a chest computed tomography (CT) with i.v. contrast showed a likely 3 cm area of active contrast in left lower lung. Chest tube placement revealed about 2 liters of blood. The patient was subsequently found to have pulmonary AVM. A successful embolisation of AVM followed by lung atipic resection involving AVM and decortication for lung re-expansion were the treatments provided. Conclusions: Women with known pulmonary AVM should be maximally treated prior to becoming pregnant, and the physician should be alert to complications of pulmonary AVM during pregnancy.

Relevance of BRAF(V600E) mutation testing versus RAS point mutations and RET/PTC rearrangements evaluation in the diagnosis of thyroid cancer

BACKGROUND

A molecular profile including BRAF and RAS mutations as well as RET/PTC rearrangement evaluation has been proposed to provide an accurate presurgical assessment of thyroid nodules and to reduce the number of unnecessary diagnostic surgeries, sparing patients' health and saving healthcare resources. However, the application of such molecular analyses may provide different results among different centers and populations in real-life settings. Our aims were to evaluate the diagnostic utility of assessing the presence of BRAF and RAS mutations and RET/PTC1 and RET/PTC3 rearrangements in all cytological categories in an Italian group of thyroid nodule patients assessed prospectively, and to understand whether and which mutation testing might be helpful in cytologically indeterminate nodules.

METHODS

A total of 911 patients were submitted to ultrasound and fine-needle aspiration biopsy examination. Cytological evaluation was performed in parallel with molecular testing and compared to pathological results in 940 thyroid nodules, including 140 indeterminate lesions.

RESULTS

BRAF mutation testing provided the best contribution to cancer diagnosis, allowing the disease to be detected at an early stage, and identifying indeterminate nodules in which diagnostic lobectomy could be spared. On the contrary, RAS and RET/PTC analysis did not further increase diagnostic sensitivity for thyroid cancer. In addition, we found RET/PTC rearrangements in benign lesions, indicating that this molecular marker might not be useful for the detection of thyroid cancer.

CONCLUSION

BRAF(V600E) mutation analysis is superior to RAS point mutations and evaluation of RET/PTC rearrangements in the diagnosis of thyroid cancer, even in indeterminate lesions.