Familial thyroid carcinoma: a diagnostic algorithm

Expanding Our Knowledge of DICER1 Gene Alterations and Their Role in Thyroid Diseases

Mutations in DICER1, a gene involved in RNA interference, have been associated with a wide range of multi-organ neoplastic and non-neoplastic conditions. Historically known for its association with pleuropulmonary blastoma, DICER1 syndrome has received more attention due to the association with newly discovered diseases and tumors. Recent studies evaluating DICER1 mutations and DICER1-driven thyroid disease in both pediatric and adult thyroid nodules revealed thyroid disease as the most common manifestation of DICER1 mutations. This study undertakes a comprehensive investigation into DICER1 mutations, focusing on their role in thyroid diseases. Specific attention was given to thyroid follicular nodular disease and differentiated thyroid carcinomas in infancy as highly indicative of germline DICER1 mutation or DICER1 syndrome. Additionally, poorly differentiated thyroid carcinoma and thyroblastoma were identified as potential indicators of somatic DICER1 mutations. Recognizing these manifestations should prompt clinicians to expedite genetic evaluation for this neoplastic syndrome and classify these patients as high risk for additional multi-organ malignancies. This study comprehensively synthesizes the current knowledge surrounding this genetically associated entity, providing intricate details on histologic findings to facilitate its diagnosis.

FAMILIAL NON-MEDULLARY THYROID CARCINOMA

BACKGROUND

Familial non-medullary thyroid carcinoma (FNMTC) is defined as cancer developing in two or more first-degree relatives if predisposing factors, for example, radiation, are absent. The disease can be either syndromic, when it is a component of complex genetic syndromes, or non-syndromic (95% cases). The genetic basis of non-syndromic FNMTC is unknown; the clinical behavior of tumorsis unclear and, at times, contradictory.

AIM

To analyze clinical manifestations of FNMTC and compare them with the data for sporadic papillary thyroid carcinomas in patients of the same age groups.

MATERIALS AND METHODS

We examined 22 patients (a "parents" group and a "children" group) suffering from the non-syndromic FNMTC. For comparison, two groups of sporadic papillary carcinomas patients of the same age were drawn up("adult" and "young"). We analyzed tumor size and frequency of the distributionby the categoryof TNM system, invasiveness, multifocality, metastases to lymph nodes, type and extent of surgical and radioiodine treatment, and prognosis according to the MACIS criterion.

RESULTS

Whether sporadic or familial, the tumor size, metastatic potential, and invasive potential are higher in young people, asalready known. There was no significant difference between the "parents" and "adult" groups of patients in terms of tumor parameters. One exception was the higher frequency of multifocal tumors in the FNMTC patients. Meanwhile, compared to the "young" sporadic papillary carcinomas patients, the FNMTC "children" had a higher frequency of T2 tumors, metastasizing (N1a-N1ab), and multifocal tumors, but a lower frequency of carcinomas with intrathyroidal invasions.In the FNMTC "children" compared to FNMTC "parents" was a higher frequency of T2 tumors, metastasizing carcinomas, and tumors with capsular invasion.

CONCLUSION

FNMTC carcinomas are more aggressive than sporadic ones, especially in patients who are first-degree relatives in a family with parents already diagnosed with the disease.

Overview of the 2022 WHO Classification of Familial Endocrine Tumor Syndromes

This review of the familial tumor syndromes involving the endocrine organs is focused on discussing the main updates on the upcoming fifth edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. This review emphasizes updates on histopathological and molecular genetics aspects of the most important syndromes involving the endocrine organs. We describe the newly defined Familial Cancer Syndromes as MAFA-related, MEN4, and MEN5 as well as the newly reported pathological findings in DICER1 syndrome. We also describe the updates done at the new WHO on the syndromic and non-syndromic familial thyroid diseases. We emphasize the problem of diagnostic criteria, mention the new genes that are possibly involved in this group, and at the same time, touching upon the role of some immunohistochemical studies that could support the diagnosis of some of these conditions. As pathologists play an important role in identifying tumors within a familial cancer syndrome, we highlight the most important clues for raising the suspicious of a syndrome. Finally, we highlight the challenges in defining these entities as well as determining their clinical outcome in comparison with sporadic tumors. Instead of the usual subject review, we present the highlights of the updates on familial cancer syndromes by answering select questions relevant to practicing pathologists.

Ultrasound Guided Thyroid Biopsy

Thyroid nodules are extremely prevalent among older adults, and pose a challenge due to the frequency in which they are incidentally encountered. Approximately 5% of all nodules are malignant. Ultrasound is the first line tool to evaluate thyroid nodules, and can help identify nodules that are high-risk for malignancy. Fine needle aspiration (FNA) is an excellent low-risk procedure used to evaluate suspicious thyroid nodules and identify thyroid malignancy. It is performed with a 22-27-gauge needle under ultrasound guidance. Core needle biopsy (CNB) is usually not required; however, it can be helpful if FNA is non-diagnostic or inconclusive. On-site pathologist evaluation can help determine which patients need additional sampling. CNB is usually performed with a trocar technique using an 18-gauge biopsy device under ultrasound guidance. Complications from thyroid biopsy are rare, and the most common complications are discomfort, small to moderate hematoma, and insufficient sampling. Although rare, a rapidly expanding large hematoma can cause airway compression requiring intubation and surgery to preserve the airway and achieve hemostasis. Following biopsy, approximately 10.8% of thyroid nodules will require surgical excision.

Identification of SPRY4 as a Novel Candidate Susceptibility Gene for Familial Nonmedullary Thyroid Cancer

Background: The molecular basis of familial nonmedullary thyroid cancer (FNMTC) is still poorly understood, representing a limitation for molecular diagnosis and clinical management. In this study, we aimed to identify new susceptibility genes for FNMTC through whole-exome sequencing (WES) analysis of leukocyte DNA of patients from a highly informative FNMTC family. Methods: We selected six affected family members to conduct WES analysis. Bioinformatic analyses were undertaken to filter and select the genetic variants shared by the affected members, which were subsequently validated by Sanger sequencing. To select the most likely pathogenic variants, several studies were performed, including family segregation analysis, in silico impact characterization, and gene expression (messenger RNA and protein) depiction in databases. For the most promising variant identified, we performed in vitro studies to validate its pathogenicity. Results: Several potentially pathogenic variants were identified in different candidate genes. After filtering with appropriate criteria, the variant c.701C>T, p.Thr234Met in the SPRY4 gene was prioritized for in vitro functional characterization. This SPRY4 variant led to an increase in cell viability and colony formation, indicating that it confers a proliferative advantage and potentiates clonogenic capacity. Phosphokinase array and Western blot analyses suggested that the effects of the SPRY4 variant were mediated through the mitogen-activated protein kinase/extracellular signal-regulated kinase pathway, which was further supported by a higher responsiveness of thyroid cancer cells with the SPRY4 variant to a MEK inhibitor. Conclusions: WES analysis in one family identified SPRY4 as a likely novel candidate susceptibility gene for FNMTC, allowing a better understanding of the cellular and molecular mechanisms underlying thyroid cancer development.

A pathogenic variant in CHEK2 shows a founder effect in Portuguese Roma patients with thyroid cancer

PURPOSE

Germline mutations in DNA repair-related genes have been recently reported in cases with familial non-medullary thyroid carcinoma (FNMTC). A Portuguese family from the Roma ethnic group with four members affected with papillary thyroid carcinoma (PTC), and three members with multinodular goiter (MNG) was identified. The aim of this study was to investigate the involvement of DNA repair-related genes in the etiology of FNMTC in this family and in the Roma ethnic group.

METHODS

Ninety-four hereditary cancer predisposition genes were analyzed through next-generation sequencing. Sanger sequencing was used for variant confirmation and screening. Twelve polymorphic markers were genotyped for haplotype analysis in the CHEK2 locus.

RESULTS

A germline pathogenic frameshift variant in the CHEK2 gene [c.596dupA, p.(Tyr199Ter)] was detected in homozygosity in the proband (PTC) and in his brother (MNG), being heterozygous in his mother (PTC), two sisters (PTC), and one nephew (MNG). This variant was absent in 100 general population controls. The screening of the CHEK2 variant was extended to other Roma individuals, being detected in 2/33 Roma patients with thyroid cancer, and in 1/15 Roma controls. Haplotype segregation analysis identified a common ancestral core haplotype (Hcac), covering 10 Mb in the CHEK2 locus, shared by affected CHEK2 variant carriers. Analysis of 62 individuals CHEK2 wild-type indicated that none presented the Hcac haplotype. The estimated age for this variant suggested that it was transmitted by a relatively recent common ancestor.

CONCLUSIONS

We identified a founder CHEK2 pathogenic variant, which is likely to underlie thyroid cancer and other cancer manifestations in the Roma population.

Cribriform-Morular Thyroid Carcinoma Is a Distinct Thyroid Malignancy of Uncertain Cytogenesis

Tumors with papillary cribriform and morular architecture were initially considered to be variants of papillary thyroid carcinoma; however, recent observations have challenged this view. In this study, we reviewed the demographical, histopathological, and immunohistochemical features of the largest case series, consisting of 33 tumors. The age at time of pathological diagnosis ranged from 18 to 59 (mean 33) years, and all patients except one were female. Sixteen patients had multifocal and fifteen had unifocal disease. The status of focality was unavailable in two patients. Tumors were well-circumscribed, ranging in size from 0.1 to 8.0 cm. The cribriform component was admixed with morulae in the majority, except seven had a cribriform-predominant architecture and two had predominantly solid growth. Variable degrees of nuclear enlargement, elongation, overlapping, and grooves were seen but florid nuclear convolution, intranuclear pseudoinclusions, and optically clear nuclei due to chromatin margination were not appreciated. There was no or little colloid material within the cribriform spaces. Two solid tumors had high-grade features. Immunohistochemical studies showed beta-catenin nuclear and cytoplasmic positivity in all cases. The cribriform component was positive for TTF1 and negative for thyroglobulin. PAX8 was absent in half of these tumors and focal in the remainder. Morulae were positive for keratin 5 and CD5 and negative for p63, p40, TTF1, and PAX8. Molecular studies revealed germline APC mutations in 12 tumors and were negative in 5 sporadic tumors in a subset of tested tumors. Irrespective of the antibody used in this cohort, all cribriform-morular carcinomas express TTF1; however, PAX8 immunoreactivity is weak, focal or negative, and all tumors lack thyroglobulin reactivity; these findings raise questions about tumor cell origin and may indicate that these are not of thyroid follicular epithelial differentiation. We postulate that morulae may represent divergent thymic/ultimobranchial pouch-related differentiation. Given their unique cytomorphology, immunohistochemical profiles, and genetic features that have little overlap with traditional follicular cell-derived thyroid carcinomas, we propose that these tumors represent a distinct form of thyroid carcinoma unrelated to other neoplasms of thyroid follicular cells.

Inherited Follicular Epithelial-Derived Thyroid Carcinomas: From Molecular Biology to Histological Correlates

Cancer derived from thyroid follicular epithelial cells is common; it represents the most common endocrine malignancy. The molecular features of sporadic tumors have been clarified in the past decade. However the incidence of familial disease has not been emphasized and is often overlooked in routine practice. A careful clinical documentation of family history or familial syndromes that can be associated with thyroid disease can help identify germline susceptibility-driven thyroid neoplasia. In this review, we summarize a large body of information about both syndromic and non-syndromic familial thyroid carcinomas. A significant number of patients with inherited non-medullary thyroid carcinomas manifest disease that appears to be sporadic disease even in some syndromic cases. The cytomorphology of the tumor(s), molecular immunohistochemistry, the findings in the non-tumorous thyroid parenchyma and other associated lesions may provide insight into the underlying syndromic disorder. However, the increasing evidence of familial predisposition to non-syndromic thyroid cancers is raising questions about the importance of genetics and epigenetics. What appears to be "sporadic" is becoming less often truly so and more often an opportunity to identify and understand novel genetic variants that underlie tumorigenesis. Pathologists must be aware of the unusual morphologic features that should prompt germline screening. Therefore, recognition of harbingers of specific germline susceptibility syndromes can assist in providing information to facilitate early detection to prevent aggressive disease.

Consensus statement by the American Association of Clinical Endocrinology (AACE) and the American Head and Neck Society Endocrine Surgery Section (AHNS-ES) on Pediatric Benign and Malignant Thyroid Surgery

OBJECTIVES

To provide a clinical disease state review of recent relevant literature and to generate expert consensus statements regarding the breadth of pediatric thyroid cancer diagnosis and care, with an emphasis on thyroid surgery. To generate expert statements to educate pediatric practitioners on the state-of-the-art practices and the value of surgical experience in the management of this unusual and challenging disease in children.

METHODS

A literature search was conducted and statements were constructed and subjected to a modified Delphi process to measure the consensus of the expert author panel. The wording of statements, voting tabulation, and statistical analysis were overseen by a Delphi expert (J.J.S.).

RESULTS

Twenty-five consensus statements were created and subjected to a modified Delphi analysis to measure the strength of consensus of the expert author panel. All statements reached a level of consensus, and the majority of statements reached the highest level of consensus.

CONCLUSION

Pediatric thyroid cancer has many unique nuances, such as bulky cervical adenopathy on presentation, an increased incidence of diffuse sclerosing variant, and a longer potential lifespan to endure potential complications from treatment. Complications can be a burden to parents and patients alike. We suggest that optimal outcomes and decreased morbidity will come from the use of advanced imaging, diagnostic testing, and neural monitoring of patients treated at high-volume centers by high-volume surgeons.

Consensus Statement by the American Association of Clinical Endocrinology (AACE) and the American Head and Neck Society Endocrine Surgery Section (AHNS) on Pediatric Benign and Malignant Thyroid Surgery

OBJECTIVES

To provide a clinical disease state review of recent relevant literature and to generate expert consensus statements regarding the breadth of pediatric thyroid cancer diagnosis and care, with an emphasis on thyroid surgery. To generate expert statements to educate pediatric practitioners on the state-of-the-art practices and the value of surgical experience in the management of this unusual and challenging disease in children.

METHODS

A literature search was conducted and statements were constructed and subjected to a modified Delphi process to measure the consensus of the expert author panel. The wording of statements, voting tabulation, and statistical analysis were overseen by a Delphi expert (J.J.S.).

RESULTS

Twenty-five consensus statements were created and subjected to a modified Delphi analysis to measure the strength of consensus of the expert author panel. All statements reached a level of consensus, and the majority of statements reached the highest level of consensus.

CONCLUSION

Pediatric thyroid cancer has many unique nuances, such as bulky cervical adenopathy on presentation, an increased incidence of diffuse sclerosing variant, and a longer potential lifespan to endure potential complications from treatment. Complications can be a burden to parents and patients alike. We suggest that optimal outcomes and decreased morbidity will come from the use of advanced imaging, diagnostic testing, and neural monitoring of patients treated at high-volume centers by high-volume surgeons.

65 YEARS OF THE DOUBLE HELIX: Endocrine tumour syndromes in children and adolescents

As medicine is poised to be transformed by incorporating genetic data in its daily practice, it is essential that clinicians familiarise themselves with the information that is now available from more than 50 years of genetic discoveries that continue unabated and increase by the day. Endocrinology has always stood at the forefront of what is called today 'precision medicine': genetic disorders of the pituitary and the adrenal glands were among the first to be molecularly elucidated in the 1980s. The discovery of two endocrine-related genes, GNAS and RET, both identified in the late 1980s, contributed greatly in the understanding of cancer and its progression. The use of RET mutation testing for the management of medullary thyroid cancer was among the first and one of most successful applications of genetics in informing clinical decisions in an individualised manner, in this case by preventing cancer or guiding the choice of tyrosine kinase inhibitors in cancer treatment. New information emerges every day in the genetics or system biology of endocrine disorders. This review goes over most of these discoveries and the known endocrine tumour syndromes. We cover key genetic developments for each disease and provide information that can be used by the clinician in daily practice.

Surgical Management of Familial Papillary Thyroid Microcarcinoma: A Single Institution Study of 94 Cases

BACKGROUND

Familial papillary thyroid carcinoma (familial PTC) is well known to present with aggressiveness; however, the characteristics and the prognostic outcomes of familial papillary thyroid microcarcinoma (familial micro-PTC) are not well established. The overall aim of this study was to analyze the clinicopathological outcomes of familial micro-PTC.

METHODS

Between 1996 and 2006, 2071 patients underwent thyroid surgery for papillary thyroid carcinoma. The clinicopathological outcomes for familial PTC and sporadic PTC were compared, and familial micro-PTC data were sub-analyzed.

RESULTS

There were significant differences in multifocality, bilaterality, extent of surgery, and recurrence between familial PTC and sporadic PTC (p<0.05). There was no significant difference in the number of affected family members in the familial PTC group. In patients with familial micro-PTC, less aggressiveness was noted in multifocality, extrathyroidal invasion, tumor stage at time of initial surgery, central lymph node metastasis, and recurrence than in those with familial PTC tumors>1 cm in diameter (p<0.05). The multivariate analysis including recurrence showed no significant difference between familial micro-PTC patients and sporadic micro-PTC patients.

CONCLUSION

When familial PTC was compared with sporadic PTC, our results support the recommendation for more invasive familial PTC surgery. However, familial micro-PTC outcomes differed from familial PTC tumors>1.0 cm in diameter. It was similar to sporadic micro-PTC, illustrating that familial micro-PTC is less aggressive and that a less invasive surgical treatment could be considered.

A distinct variant of papillary thyroid carcinoma indicating familial adenomatous polyposis (FAP): a case report and brief review

BACKGROUND

Familial adenomatous polyposis (FAP) is an autosomal dominantly inherited intestinal polyposis syndrome with an incidence of about 1/8300 births and accounts for about 1% of all colorectal cancers. It has a spectrum of extra-intestinal manifestations including thyroid carcinoma which occur in 1-2% of affected. The cribriform morular variant (CMV) is a rare but distinct histological subtype of papillary thyroid carcinoma (PTC) associated with FAP. Most of the reported cases describe the above entity in the background of well-established FAP. We report a case where both entities presenting simultaneously in a previously undiagnosed patient with FAP without a family history of polyposis.

CASE PRESENTATION

A 24 year old Asian female presented to the surgical clinic with a goitre of eight months duration and recent onset of altered bowel habits with features of anaemia. She was previously healthy and there was no family history of adenomatous polyposis, colorectal carcinoma or thyroid neoplasms. Colonoscopy revealed large bowel polyposis and fine needle aspiration of thyroid revealed a smear suspicious for malignancy. She underwent total thyroidectomy which revealed CMV PTC. Histology was characterized by a prominent cribriform pattern of growth with interspersed cell clusters arranged as morules along with papillary structures which are the key features of this subtype.

CONCLUSION

Diagnosis of CMV warrants ruling out of underlying FAP, irrespective of family history or gastrointestinal symptoms.

Familial Endocrine Syndromes

Endocrine tumors may present as sporadic events or as part of familial endocrine syndromes. Familial endocrine syndromes (or inherited tumor/neoplasm syndromes) are characterized by multiple tumors in multiple organs. Some morphologic findings in endocrine tumor histopathology may prompt the possibility of familial endocrine syndromes, and these recognized histologic features may lead to further molecular genetic evaluation of the patient and family members. Subsequent evaluation for these syndromes in asymptomatic patients and family members may then be performed by genetic screening.

Precursor lesions of endocrine system neoplasms

The concept of precursor lesions of endocrine neoplasms is a new and interesting topic in endocrine pathology. A variety of clinicopathological conditions are associated with a sequence of cellular changes from hyperplasia to neoplasia; dysplasia is, in contrast, quite rare. The majority of precursor lesions is associated with familial genetic syndromes. These include C-cell hyperplasia in thyroid that is associated with familial medullary thyroid carcinoma, adrenal medullary hyperplasia as a precursor of phaeochromocytomas in MEN2 syndrome, rare pituitary adenohypophyseal cell hyperplasia in familial syndromes associated with pituitary adenomas, MEN1-related precursor gastric enterochromaffin-like cell (ECL) hyperplasia, and duodenal gastrin producing (G) and/or somatostatin producing (D) cell hyperplasia that give rise to type II gastric neuroendocrine tumours (NETs) and duodenal NETs, respectively, and MEN1- or VHL-related islet hyperplasia, islet dysplasia and ductulo-insular complexes that are associated with pancreatic NETs. Other hyperplasias are not thought to be associated with genetic predisposition. Some are attributed to inflammation; autoimmune chronic atrophic gastritis-related ECL hyperplasia can progress to type I gastric NETs, and EC (enterochromaffin) cell or L cell hyperplasia associated with inflammatory bowel diseases can progress to colorectal NETs. In the lung, diffuse idiopathic pulmonary neuroendocrine cell hyperplasia can give rise to peripherally-located low grade pulmonary NETs and tumourlets (neuroendocrine microtumours <5  mm). Rarely, secondary hyperplasias develop into autonomous neoplasms, as in tertiary hyperparathyroidism or pituitary thyrotroph adenomas in primary hypothyroidism. While some precursor lesions, such as thyroid C cell hyperplasia, represent frankly premalignant conditions, others may represent a sequence of proliferative changes from hyperplasia to benign neoplasia that may also progress to malignancy.

RET gene abnormalities and thyroid disease: who should be screened and when

Mutations in the RET proto-oncogene have been implicated in the pathogenesis of several forms of medullary thyroid cancer (MTC). Multiple endocrine neoplasia type 2 (MEN-2) is an autosomal dominant syndrome caused by germline activating mutations of the RET proto-oncogene and has been categorized into three distinct clinical forms. MEN-2A is associated with MTC, bilateral pheochromocytoma, and primary hyperparathyroidism. MEN-2B is associated with MTC, bilateral pheochromocytoma, and mucosal neuromas. The rarest clinical form of MEN-2 is familial MTC (FMTC), which is also associated with MTC, but other endocrinopathies are characteristically not present. Each clinical form of MEN-2 results from a specific RET gene mutation, with a strong correlation of phenotype expression with regard to the onset and course of MTC and the presence of other endocrine tumors and a corresponding genotype. Recommendations for screening of RET mutations are necessary as their presence or absence will influence interventional strategies such as the timing of a prophylactic thyroidectomy and extent of surgery. Timing of screenings and development of interventional strategies are extremely important in caring for patients with certain RET mutations as evidence of metastatic MTC has been documented as early as 6 years of age. Interventional strategies should consider the risks of complications of these interventions based on certain characteristics of each individual case such as age of the patient, course of disease in affected family members, and the invasiveness of any proposed surgical procedure.

Familial follicular cell-derived thyroid carcinoma

Follicular cell-derived well-differentiated thyroid cancer, papillary (PTC) and follicular thyroid carcinomas comprise 95% of all thyroid malignancies. Familial follicular cell-derived well-differentiated thyroid cancers contribute 5% of cases. Such familial follicular cell-derived carcinomas or non-medullary thyroid carcinomas (NMTC) are divided into two clinical-pathological groups. The syndromic-associated group is composed of predominately non-thyroidal tumors and includes Pendred syndrome, Warner syndrome, Carney complex (CNC) type 1, PTEN-hamartoma tumor syndrome (PHTS; Cowden disease), and familial adenomatous polyposis (FAP)/Gardner syndrome. Other conditions with less established links to the development of follicular cell-derived tumors include ataxia-telangiectasia syndrome, McCune Albright syndrome, and Peutz-Jeghers syndrome. The final group encompasses syndromes typified by NMTC, as well as pure familial (f) PTC with or without oxyphilia, fPTC with multinodular goiter, and fPTC with papillary renal cell carcinoma. This heterogeneous group of diseases does not have the established genotype-phenotype correlations known as in the familial C-cell-derived tumors or medullary thyroid carcinomas (MTC). Clinicians should have the knowledge to identify the likelihood of a patient presenting with thyroid cancer having an additional underlying familial syndrome stemming from characteristics by examining morphological findings that would alert pathologists to recommend that patients undergo molecular genetic evaluation. This review discusses the clinical and pathological findings of patients with familial PTC, such as FAP, CNC, Werner syndrome, and Pendred syndrome, and the heterogeneous group of familial PTC.

Familial papillary thyroid carcinoma: a retrospective analysis

Background. Whether or not the familial form of papillary thyroid carcinoma is more aggressive than the sporadic form of the disease remains controversial. Methods. To explore this question and whether or not increased aggressiveness is more apparent in families with multiple affected members, we performed a chi square by trend analysis on our patients clinical and pathologic data comparing: first degree families with three or more affected members versus first degree families with two affected members versus sporadic cases of papillary thyroid carcinoma. Results. No statistically significant trends were seen for any presenting surgical pathology parameter, age at presentation, length of follow-up or gender distribution. The familial groups exhibited significant trends for higher rates of reoperation (P = 0.05) and/or requiring additional radioactive iodine therapy (P = 0.03), distant metastases (P = 0.003) and deaths (P = 0.01). These aggressive features were most apparent in certain families with three or more affected members. Conclusions. Using the chi square by trend analysis, a significant trend was seen for the familial form of papillary thyroid cancer to possess more aggressive features than the sporadic disease. Prompt recognition of the familial nature of the disease may provide earlier diagnosis and treatment in similarly affected family members.

Familial thyroid cancer: a review

Thyroid carcinomas can be sporadic or familial. Familial syndromes are classified into familial medullary thyroid carcinoma (FMTC), derived from calcitonin-producing C cells, and familial non-medullary thyroid carcinoma, derived from follicular cells. The familial form of medullary thyroid carcinoma (MTC) is usually a component of multiple endocrine neoplasia (MEN) IIA or IIB, or presents as pure FMTC syndrome. The histopathological features of tumors in patients with MEN syndromes are similar to those of sporadic tumors, with the exception of bilaterality and multiplicity of tumors. The genetic events in the familial C-cell-derived tumors are well known, and genotype-phenotype correlations well established. In contrast, the case for a familial predisposition of non-medullary thyroid carcinoma is only now beginning to emerge. Although, the majority of papillary and follicular thyroid carcinomas are sporadic, the familial forms are rare and can be divided into two groups. The first includes familial syndromes characterized by a predominance of non-thyroidal tumors, such as familial adenomatous polyposis and PTEN-hamartoma tumor syndrome, within others. The second group includes familial syndromes characterized by predominance of papillary thyroid carcinoma (PTC), such as pure familial PTC (fPTC), fPTC associated with papillary renal cell carcinoma, and fPTC with multinodular goiter. Some characteristic morphologic findings should alert the pathologist of a possible familial cancer syndrome, which may lead to further molecular genetics evaluation.

[Familial thyroid carcinomas]

Approximately 5% of differentiated thyroid carcinomas with follicular cell differentiation, papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) and 25-30% of medullary thyroid carcinoma (MTC) are hereditary. They occur either as part of a defined syndrome or are confined to the thyroid gland. Compared to their sporadic non-hereditary counterparts hereditary thyroid carcinomas generally develop earlier and regularly show multifocal tumour growth. With the exception of familial MTC, which is preceded by neoplastic C cell hyperplasia, no precursor lesions of hereditary thyroid carcinoma are known. In strong correlation with the localisation of the germline mutation of the RET protooncogene, familial MTC shows a distinct clinical course which allows precise clinical decision-making for prophylactic thyroidectomy to prevent invasive MTC. According to current knowledge prophylactic thyroidectomy of all other types of hereditary thyroid carcinoma is not justified.

Thyroid pathology in PTEN-hamartoma tumor syndrome: characteristic findings of a distinct entity

BACKGROUND

Phosphatase and tensin homolog deleted on chromosome ten (PTEN)-hamartoma tumor syndrome (PHTS) is a complex disorder caused by germline inactivating mutations of the PTEN tumor suppressor gene. PHTS includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), and Proteus-like syndromes. Affected individuals develop both benign and malignant tumors in a variety of tissues, including the thyroid. This study is to better characterize and describe the thyroid pathology within the different entities of this syndrome, and examine whether there is an association between specific thyroid findings and different PTEN mutations.

METHODS

Twenty patients with known PTEN mutations, and/or clinical diagnosis of PHTS, and thyroid pathology were identified: 14 with CS and 6 with BRRS.

RESULTS

Thyroid pathology findings were as follows: multiple adenomatous nodules in a background of lymphocytic thyroiditis (LT) in 75%, papillary carcinoma in 60%, LT alone in 55%, follicular carcinoma in 45%, C-cell hyperplasia in 55%, and follicular adenomas in 25%. Within the papillary carcinoma group, there were 6 microcarcinomas, 5 follicular variants, and 1 classical type.

CONCLUSIONS

There were no morphologic differences between the thyroid findings in CS and BRRS. Also, there was no correlation between specific PTEN germline mutations (exons 5, 6, and 8) and pathologic findings. Distinctive and characteristic findings in PHTS include multiple unique adenomatous nodules in a background of LT, and C-cell hyperplasia; it is vital that pathologists recognize the classical histologic features of this syndrome to alert clinicians to the possibility of this syndrome in their patients.

Familial follicular cell tumors: classification and morphological characteristics

Familial follicular cell-derived well-differentiated thyroid cancer, papillary (PTC), and follicular thyroid carcinomas (FTC), accounts for 95% of thyroid malignancies. The majority of are sporadic, and at least 5% of these patients will have familial disease. Familial thyroid syndromes are classified into familial medullary thyroid carcinoma (FMTC), derived from calcitonin-producing C cells, and familial follicular cell tumors or non-medullary thyroid carcinoma (FNMTC), derived from follicular cells. Twenty-five percent of patients with medullary thyroid cancer (MTC) have a familial form; however, this accounts for only 1% of all patients with thyroid cancer. The familial follicular cell-derived lesions or familial non-medullary thyroid cancer can be divided into two clinical-pathological groups. The first group includes familial syndromes characterized by a predominance of non-thyroidal tumors, such as familial adenomatous polyposis (FAP), PTEN-hamartoma tumor syndrome (Cowden disease; PHTS), Carney complex, Werner syndrome, and Pendred syndrome. The second group includes familial syndromes characterized by predominance of papillary thyroid carcinoma (PTC), such as pure fPTC, fPTC associated with papillary renal cell carcinoma, and fPTC with multinodular goiter. Most of the progress in the genetics of familial thyroid cancer has been in patients with MTC. This is usually a component of multiple endocrine neoplasias IIA or IIB, or as pure familial medullary thyroid carcinoma syndrome. The genetic events in the familial C-cell-derived tumors are known and genotype-phenotype correlations are well established. The mutations in patients with isolated NMFTC have not been as well defined as in MTC. In many cases, patients have a known familial syndrome that has defined risk for thyroid cancer. The clinician must be knowledgeable in recognizing the possibility of an underlying familial syndrome when a patient presents with thyroid cancer. Some characteristic thyroid morphologic findings should alert the pathologist of a possible familial cancer syndrome, which may lead to further molecular genetics evaluation.

Thyroid cancer of follicular cell origin in inherited tumor syndromes

Well-differentiated thyroid cancer accounts for 95% of thyroid malignancies. In contrast to medullary thyroid carcinoma, in which about 25% are familial, only 5% of follicular cell-derived thyroid carcinomas are a component of a familial cancer syndrome. The familial follicular cell-derived tumors or nonmedullary thyroid carcinoma encompass a heterogeneous group of diseases, and are classified into 2 distinct groups: syndromic-associated tumors, occurring in syndromes in which nonmedullary thyroid carcinomas are the predominant tumor encountered, and nonsyndromic tumors, those occurring in tumor syndromes in which thyroid involvement is a minor component. The first group, syndromic-associated tumors, includes phosphase and tensin (PTEN)-hamartoma tumor syndrome/Cowden syndrome, familial adenomatous polyposis/Gardner syndrome, Carney complex type 1, Werner syndrome, and Pendred syndrome. Other syndromes, as McCune Albright syndrome, Peutz-Jeghers syndrome, and Ataxia-teleangiectasia syndrome may be associated with the development of follicular cell-derived tumors, but the link is less established than the above syndromes. The syndromic-associated tumors are the focus of this review. The second group of familial follicular cell-derived tumors syndromes or nonsyndromic tumors, in which nonmedullary thyroid carcinomas are the major findings, include pure familial papillary thyroid carcinoma, with or without oxyphilia, familial papillary thyroid carcinoma with papillary renal cell carcinoma, and familial papillary thyroid carcinoma with multinodular goiter. This review will discuss the clinical and pathological findings of the patients with familial syndrome-associated tumors: PTEN-hamartoma tumor syndrome/Cowden syndrome, familial adenomatous polyposis syndrome, Carney complex type 1, Werner syndrome, and Pendred syndrome.

Neuroendocrine tumors and tumor syndromes in childhood

Endocrine and neuroendocrine cells form a large and diverse array of cell types. They are present in the form of specialized organs, such as the pituitary, parathyroid, thyroid, and adrenal gland, or in the form of the diffuse neuroendocrine system in the respiratory and digestive tracts. Neuroendocrine tumors are a heterogeneous group of neoplasms, yet they present certain unifying features. These include frequent hormonal overproduction that leads to specific symptoms and a typical immunohistochemical staining profile with chromogranin A and synaptophysin reactivity. Over the past decades, many neuroendocrine tumors have been described in the context of heritable tumor syndromes, and there exist several syndromes that are almost entirely composed of neuroendocrine tumors. Tumors occurring as part of these hereditary syndromes are characterized by specific genetic abnormalities that have helped our understanding of tumorigenesis, and they frequently appear at a young age. It is therefore important for the pediatric pathologist to be aware of specific histologic characteristics of neuroendocrine tumors in childhood and of their association with specific tumor syndromes. This may alert other clinicians to the possibility of multiple tumors in the patient or his family members. This review focuses on hereditary syndromes with neuroendocrine tumors, including multiple endocrine neoplasia types 1 and 2, Von Hippel-Lindau disease, neurofibromatosis type 1, Carney complex, pheochromocytoma-paraganglioma syndrome, and familial nonmedullary thyroid carcinoma. In addition, several individual neuroendocrine tumors are described, such as medullary thyroid carcinoma, gastroenteropancreatic tumors, pheochromocytoma, and paraganglioma, emphasizing specific histopathologic characteristics.

Familial syndromes associated with thyroid cancer in the era of personalized medicine

BACKGROUND

Well-differentiated thyroid cancer accounts for 95% of thyroid malignancies, and 5% of these patients will have familial disease. This compares to 25% of patients with medullary thyroid cancer (MTC) having a familial form; however, this accounts for only 1% of all patients with thyroid cancer. Most cases of familial thyroid cancer are nonmedullary (NMFTC), and have been shown to be present in familial cancer syndromes such as familial adenomatous polyposis, Cowden syndrome, Carney complex, Pendred syndrome, and Werner syndrome. This review discusses the contemporary management of the patients with familial-syndrome-associated thyroid cancer based on their individual risks for developing thyroid cancer.

SUMMARY

Most of the progress in the genetics of familial thyroid cancer has been in patients with MTC. The mutations in patients with isolated NMFTC have not been as well defined as in MTC. They are likely autosomal dominant with reduced penetrance. The patients with these familial syndromes most likely have a susceptibility gene that increases the risk of thyroid cancer. Most of the patients with a familial syndrome and NMFTC will have papillary thyroid carcinoma, suggesting that a specific gene for papillary thyroid carcinoma may also be present. In many cases, patients have a known familial syndrome that has defined risk for thyroid cancer.

CONCLUSIONS

Patients with familial syndromes that are associated with thyroid cancer can be individually categorized based on syndrome risks for developing thyroid cancer. The clinician must also be knowledgeable in recognizing the possibility of an underlying familial syndrome when a patient presents with thyroid cancer.

Surgical management of nonmultiple endocrine neoplasia endocrinopathies: state-of-the-art review

The development of genetic testing has given patients with familial endocrine diseases the opportunity to be identified earlier in life. The importance of this technological advancement cannot be underestimated, as some of these heritable diseases have significant potential for malignancy. This article focuses on the identification and surgical management of familial endocrinopathies of the thyroid, parathyroid, adrenal glands, and pancreas. Familial endocrinopathies discussed include hereditary nonmedullary carcinoma of the thyroid, Cowden disease, familial adenomatous polyposis, Carney complex, Werner syndrome, familial medullary thyroid carcinoma, Pendred syndrome, hereditary hyperparathyroidism jaw-tumor syndrome, familial isolated hyperparathyroidism, Beckwith- Wiedemann syndrome, Li-Fraumeni syndrome, neurofibromatosis I, von Hippel-Lindau disease, and tuberous sclerosis.

Galectin-3 regulates apoptosis and doxorubicin chemoresistance in papillary thyroid cancer cells

A subset of patients with papillary thyroid cancer (PTC) present with aggressive disease that is refractory to conventional treatment. Novel therapies are needed to treat this group of patients. Galectin-3 (Gal-3) is a beta-galactoside-binding protein with anti-apoptotic activity. Over 30 studies in the last 3 years have reported that Gal-3 is highly expressed in PTC relative to normal thyrocytes. In this study, we show that Gal-3 silencing with RNA interference stimulates apoptosis, while Gal-3 overexpression protects against both TRAIL- and doxorubicin-induced apoptosis in PTC cells. The anti-apoptotic activity and chemoresistance related to Gal-3 function can be partially reversed through the inhibition of the PI3K-Akt pathway, suggesting that Gal-3 acts, at least in part, on the PI3K-Akt axis. These observations support further evaluation of Gal-3 as a potential therapeutic target in patients with aggressive PTC.