A PATIENT WITH AN ATYPIC NECK MASS LESION.

An 81-year-old woman presented with a history of essential hypertension for eight years and an asymptomatic multinodular goiter that had been incidentally discovered on neck ultrasonography two years ago and an-isohypoechoic mass lesion located adjacent to the right lobe inferior pole of the thyroid gland. Parathyroid adenoma or lymphadenopathy were the differential diagnosis. After two years, the endocrine surgeon decided to operate her multinodular goiter and her probably benign lesion. Intraoperatively, the blood pressure and pulse rate increased markedly and intravenous antihypertensive treatment was administered. She was discharged after blood pressure control. A 2 mm micromedullary thyroid carcinoma with C-cell hyperplasia located on the left lobe of the thyroid was detected. The aforementioned mass lesion was also reported as typical cervical paraganglioma. Because of concomitant medullary thyroid carcinoma with C-cell hyperplasia and paraganglioma the patient was subjected to genetic counseling and molecular testing for hereditary cancer syndromes. A variation of the succinate dehydrogenase gene D (SDHD) NM_003002.3: c.325C> T (Gln109Term) has been reported as the disease-causing mutation. Herein we present a case diagnosed for neck paraganglioma and medullary thyroid carcinoma after an intraoperative hypertensive crisis.

The spectrum of SDHD mutations in Russian patients with head and neck paraganglioma.

AIM OF THE STUDY: It was found that the mutations in the SDHD gene, encoding one of subunits of the succinate dehydrogenase complex, lead to the development of head and neck paraganglioma (HNPGL). We analyzed this gene in 91 patients with HNPGL from Russia. MATERIALS AND METHODS: DNA was isolated from the whole blood. A screening for mutations was performed by Sanger sequencing. RESULTS: We revealed three missense mutations that have been described previously: p.Pro81Leu, p.His102Arg, p.Tyr114Cys. Moreover, we identified a novel potentially pathogenic variant (p.Trp105*). CONCLUSIONS: We found that mutations in the SDHD gene were less common in Russian patients compared with the majority of European populations. It was shown that the p.His102Arg mutation is a major mutation in Russia. We confirmed the previous suggestion that a bilateral localization of the tumor and the carotid type represent a marker of the genetically determined form of HNPGL.

Partial monosomy of 11q22.2q22.3 including the SDHD gene in individuals with developmental delay.

Deletions in the middle portion of 11q are not as well described in the literature as terminal 11q deletions that result in Jacobsen syndrome. One confounding factor in the older literature is that the G-banding pattern of 11q13q21 is very similar to 11q21q23. The advent of fluorescence in situ hybridization and later microarray technologies have allowed for a better resolution of many of these deletions, but genotype-phenotype correlations are still difficult since these deletions are rare events. We present five individuals who presented with developmental delays with de novo 11q22.2q23.3 deletions. Deletions were observed by standard G-banded chromosome analysis with clarification of breakpoints and gene content by SNP microarray analysis. Of note, all individuals had identical distal breakpoints. All deletions include SDHD, which is implicated in hereditary paraganglioma/pheochromocytoma, for which the patients will need to be monitored in adulthood. In spite of the large deletions of 8.6 Mb (Patients 1 and 3), 13.98 Mb (Patient 2), and 12.6 Mb (Patients 4 and 5) all patients show somewhat mild intellectual disability and dysmorphism.

Consanguineous couple with SDHD gene mutations: Diagnosis, treatment, and implications of family genetic testing.

The newly published clinical consensus guideline on the management of PGL/PCC is helpful for decision-making for diagnostics and treatment. Still, the treatment of patients with SDHD gene mutations requires an individual approach and those patients belong to multiprofessional teams. It is often assumed that spouses are genetically unrelated. However, the genetic relationships between spouses should always be examined empathetically and impartially.

Paraganglioma of the Right Recurrent Laryngeal Nerve Presenting as a Thyroid Nodule.

Paragangliomas are abnormal growth cells of neuroectodermal origin that arise from the autonomic nervous system. Head and neck paragangliomas are rare, commonly benign and often have a hereditary origin. Head and neck paragangliomas most commonly arise in the carotid bodies, vagus and glossopharyngeal nerves, and the sympathetic chain. However, we present a case of a paraganglioma arising from the recurrent laryngeal nerve, a phenomenon that has been reported only three times before in the literature. The patient is a 49-year-old female with a past medical history of bilateral carotid body paragangliomas and Hashimoto's disease. She has a family history of paragangliomas in her father and distant relatives and carries a pathogenic variation in the succinate-dehydrogenate subunit D (SDHD) gene, which was first identified through the original linkage studies involving her family. She presented with a mild swelling sensation in her neck. A thyroid ultrasound revealed a right lobe nodule measuring 3.3 x 2.2 x 2.1 cm. Fine needle aspiration of the nodule revealed an atypia of undetermined significance with a risk of malignancy judged as 50%. A total thyroidectomy was performed due to concern for malignancy. During the operation, the thyroid was nodular and hypervascular. At the right thyroid lobe, there was a pearlescent tubular structure approximately 4-5 mm in size. This was stimulated via intraoperative nerve monitoring and was consistent with being a part of the right recurrent laryngeal nerve. Pathology of the tubular structure revealed a 2.8 cm paraganglioma of the right recurrent laryngeal nerve. An incidental 0.1 cm papillary thyroid microcarcinoma within the left thyroid lobe was also noted. Our patient presented with a history of paragangliomas at a very young age and bilaterality, features that are highly characteristic of hereditary disease. Through the original linkage studies involving her family, her father was recognized as being an obligate carrier at risk of bearing occult paragangliomas. Imaging showed that he carried three paragangliomas. Identification of the familial SDHD syndrome as well as SDHD testing has now become widely available. Recognizing hereditary paraganglioma and other cancer susceptibility syndromes can help foster more knowledge on the subject and improve clinical outcomes. More attention should be put on the presentation of paragangliomas in an atypical location, such as in our case.

High incidence of occult familial SDHD cases amongst Czech patients with head and neck paragangliomas.

Introduction: Head and neck paragangliomas (HNPGLs) are rare neuroendocrine tumors, which are mostly benign in nature. Amongst all genes, Succinate Dehydrogenase Subunit D (SDHD) is the most commonly mutated in familial HNPGLs. In about 30% of HNPGLs, germline mutations in SDHD can also occur in the absence of positive family history, thus giving rise to "occult familial" cases. Our aim was to evaluate the pattern of SDHD germline mutations in Czech patients with HNPGLs. Materials and methods: We analyzed a total of 105 patients with HNPGLs from the Otorhinolaryngology departments of 2 tertiary centers between 2006 - 2021. All underwent complex diagnostic work-up and were also consented for genetic analysis. Results: Eighty patients aged 13-76 years were included; around 60% with multiple PGLs were males. Carotid body tumor was the most frequently diagnosed tumor. Germline SDHD mutation was found in only 12% of the Czech patients; approximately 78% of those harboring the mutation had negative family history. The mutation traits had higher affiliation for multiple tumors with nearly 70% patients of ≤ 40 years of age. Conclusion: An SDHD mutation variant was shared amongst unrelated patients but no founder-effect was established. Our findings confirmed that the pattern of SDHD mutation distribution amongst HNPGLs in Czech Republic differs from most studies worldwide.

Genetic Variants in Patients with Multiple Head and Neck Paragangliomas: Dilemma in Management.

Multiple head and neck paragangliomas (HNPGLs) are neuroendocrine tumors of a mostly benign nature that can be associated with a syndrome, precipitated by the presence of a germline mutation. Familial forms of the disease are usually seen with mutations of SDHx genes, especially the SDHD gene. SDHB mutations are predisposed to malignant tumors. We found 6 patients with multiple tumors amongst 30 patients with HNPGLs during the period of 2016 to 2021. We discuss the phenotypic and genetic patterns in our patients with multiple HNPGLs and explore the management possibilities related to the disease. Fifty percent of our patients had incidental findings of HNPGLs. Twenty-one biochemically silent tumors were found. Four patients had germline mutations, and only one had a positive family history. Three out of five underwent surgery without permanent complications. Preventative measures (genetic counselling and tumor surveillance) represent the gold standard in effectively controlling the disease in index patients and their relatives. In terms of treatment, apart from surgical and radiotherapeutic interventions, new therapeutic measures such as gene targeted therapy have contributed very sparsely. With the lack of standardized protocols, management of patients with multiple HNPGLs still remains very challenging, especially in those with sporadic or malignant forms of the disease.

Retroperitoneal Paraganglioma With Asymptomatic Follicular Lymphoma: A Case Report.

Paraganglioma (PGL) is a rare tumor originating from extra-adrenal paraganglionic chromaffin tissues, and most sympathetic PGLs have excessive catecholamine secretion. However, nonfunctional PGLs are sometimes found. Although malignant PGL is defined by metastasis to nonchromaffin tissues, it is difficult to predict malignancies due to the lack of reliable markers of potential malignancies. We report the case of a 69-year-old Japanese woman with an incidental retroperitoneal tumor and multiple enlarged mesenteric lymph nodes simultaneously. The patient had no subjective symptoms and there were no laboratory findings suggesting catecholamine hypersecretion. Both the retroperitoneal tumor and the enlarged mesenteric lymph nodes showed high accumulation of fluorodeoxyglucose (FDG), whereas metaiodobenzylguanidine (MIBG) was accumulated only at the retroperitoneal tumor. Although a retroperitoneal tumor was diagnosed as nonfunctional PGL by examination including MIBG scintigraphy, the cause of enlarged mesenteric lymph nodes could not be diagnosed by imaging and biochemical tests. As a result of retroperitoneal tumor resection and mesenteric lymph nodes sampling, histopathological examination revealed that a retroperitoneal tumor was PGL and enlarged mesenteric lymph nodes were follicular lymphoma. To reveal an underlying genetic factor, we performed whole exome sequencing of genomic DNA, and we identified 2 possible candidate variants in SDHD and DLST, but the pathogenicity of these variants remains uncertain in the present case. This rare case reinforces the importance of histopathological diagnosis of nonchromaffin tissue lesions in patients with PGL for the appropriate treatment strategy.

SDHD gene mutation in Mexican population with carotid body tumor.

INTRODUCTION: Among the U.S. population, the p81L SDHD (11q23) gene mutation is present in 6-36% of patients with sporadic carotid body tumor (CBT), but in familial cases is high as 80%. That is why the P81L mutation is used as a screening method for carotid body tumor in the U.S. METHODS: We included 25 patients who underwent resection of a CBT from January 2010 to June 2015. After informed consent, a blood sample was taken for genetic testing on real-time polymerase chain reaction, in order to identify p81L mutation in the SDHD gene. The information was analyzed with descriptive statistics, using central tendency and description measures. RESULTS: In our group, 92% were females, a mean age of 55.5 years, and 52% were Shamblin type II. The most common place of residence was Mexico City, 8% of the patients had family history, about 20% of the patients had a contralateral tumor and 16% had antecedent of another kind of tumor, 4 (16%) p81L SDHD gene mutations were detected, all of them were heterozygous. CONCLUSIONS: The p81L mutation in the SDHD gene was found in the Mexican population in higher grade that in the U.S. population, which explain the high incidence of this pathology in our country, but we need more studies about this subject.

INTRODUCCIÓN: La mutación p81L del gen SDHD (11q23) se encuentra presente en el 6-36% de los pacientes con tumores del cuerpo carotídeo (TCC) esporádicos y hasta en el 80% de los que presentan TCC familiares. En los EE.UU. se usa como método de cribado para TCC. MÉTODO: Se incluyeron 25 pacientes consecutivos operados de resección de TCC entre enero de 2010 y junio de 2015. Se les tomó muestra sanguínea venosa que se sometió a reacción en cadena de la polimerasa en tiempo real para identificar la mutación p81L del gen SDHD (11q23). La información se analizó con estadística descriptiva mediante medidas de tendencia central y dispersión. RESULTADOS: Del grupo en estudio, el 92% eran mujeres, la edad promedio era de 55.5 años y el 52% tenían tumor Shamblin tipo II. El lugar de residencia más frecuente fue la Ciudad de México. El 8% presentaban antecedentes familiares, el 20% tumor bilateral y el 16% presentaron un tumor en otra región. Se encontró la mutación p81L del gen SDHD (11q23) en el 16% de los pacientes de forma heterocigota. CONCLUSIONES: La mutación p81L del gen SDHD se encuentra presente en la población mexicana en un grado más elevado que lo reportado en los EE.UU., lo que podría explicar la alta incidencia en nuestro medio.

Growth Adaptation of gnd and sdhCB Escherichia coli Deletion Strains Diverges From a Similar Initial Perturbation of the Transcriptome.

Adaptive laboratory evolution (ALE) has emerged as a new approach with which to pursue fundamental biological inquiries and, in particular, new insights into the systemic function of a gene product. Two E. coli knockout strains were constructed: one that blocked the Pentose Phosphate Pathway (gnd KO) and one that decoupled the TCA cycle from electron transport (sdhCDAB KO). Despite major perturbations in central metabolism, minimal growth rate changes were found in the two knockout strains. More surprisingly, many similarities were found in their initial transcriptomic states that could be traced to similarly perturbed metabolites despite the differences in the network location of the gene perturbations and concomitant re-routing of pathway fluxes around these perturbations. However, following ALE, distinct metabolomic and transcriptomic states were realized. These included divergent flux and gene expression profiles in the gnd and sdhCDAB KOs to overcome imbalances in NADPH production and nitrogen/sulfur assimilation, respectively, that were not obvious limitations of growth in the unevolved knockouts. Therefore, this work demonstrates that ALE provides a productive approach to reveal novel insights of gene function at a systems level that cannot be found by observing the fresh knockout alone.

SDHD gene mutation in Mexican population whit carotid body tumor. / Mutación del gen SDHD en población mexicana con tumor del cuerpo carotídeo

Introduction: Among the U.S. population, the p81L SDHD (11q23) gene mutation is present in 6-36% of patients with sporadic carotid body tumor (CBT), but in familial cases is high as 80%. That is why the P81L mutation is used as a screening method for carotid body tumor in the U.S. Methods: We included 25 patients who underwent resection of a CBT from January 2010 to June 2015. After informed consent, a blood sample was taken for genetic testing on real-time polymerase chain reaction, in order to identify p81L mutation in the SDHD gene. The information was analyzed with descriptive statistics, using central tendency and description measures. Results: In our group, 92% were females, a mean age of 55.5 years, and 52% were Shamblin type II. The most common place of residence was Mexico City, 8% of the patients had family history, about 20% of the patients had a contralateral tumor and 16% had antecedent of another kind of tumor, 4 (16%) p81L SDHD gene mutations were detected, all of them were heterozygous. Conclusions: The p81L mutation in the SDHD gene was found in the Mexican population in higher grade that in the U.S. population, which explain the high incidence of this pathology in our country, but we need more studies about this subject.

Introducción: La mutación p81L del gen SDHD (11q23) se encuentra presente en el 6-36% de los pacientes con tumores del cuerpo carotídeo (TCC) esporádicos y hasta en el 80% de los que presentan TCC familiares. En los EE.UU. se usa como método de cribado para TCC. Método: Se incluyeron 25 pacientes consecutivos operados de resección de TCC entre enero de 2010 y junio de 2015. Se les tomó muestra sanguínea venosa que se sometió a reacción en cadena de la polimerasa en tiempo real para identificar la mutación p81L del gen SDHD (11q23). La información se analizó con estadística descriptiva mediante medidas de tendencia central y dispersión. Resultados: Del grupo en estudio, el 92% eran mujeres, la edad promedio era de 55.5 años y el 52% tenían tumor Shamblin tipo II. El lugar de residencia más frecuente fue la Ciudad de México. El 8% presentaban antecedentes familiares, el 20% tumor bilateral y el 16% presentaron un tumor en otra región. Se encontró la mutación p81L del gen SDHD (11q23) en el 16% de los pacientes de forma heterocigota. Conclusiones: La mutación p81L del gen SDHD se encuentra presente en la población mexicana en un grado más elevado que lo reportado en los EE.UU., lo que podría explicar la alta incidencia en nuestro medio.