Hürthle cell carcinoma: a critical histopathologic appraisal

Molecular Alterations and Comprehensive Clinical Management of Oncocytic Thyroid Carcinoma: A Review and Multidisciplinary 2023 Update

Importance

Oncocytic (Hürthle cell) thyroid carcinoma is a follicular cell-derived neoplasm that accounts for approximately 5% of all thyroid cancers. Until recently, it was categorized as a follicular thyroid carcinoma, and its management was standardized with that of other differentiated thyroid carcinomas. In 2022, given an improved understanding of the unique molecular profile and clinical behavior of oncocytic thyroid carcinoma, the World Health Organization reclassified oncocytic thyroid carcinoma as distinct from follicular thyroid carcinoma. The International Thyroid Oncology Group and the American Head and Neck Society then collaborated to review the existing evidence on oncocytic thyroid carcinoma, from diagnosis through clinical management and follow-up surveillance.

Observations

Given that oncocytic thyroid carcinoma was previously classified as a subtype of follicular thyroid carcinoma, it was clinically studied in that context. However, due to its low prevalence and previous classification schema, there are few studies that have specifically evaluated oncocytic thyroid carcinoma. Recent data indicate that oncocytic thyroid carcinoma is a distinct class of malignant thyroid tumor with a group of distinct genetic alterations and clinicopathologic features. Oncocytic thyroid carcinoma displays higher rates of somatic gene variants and genomic chromosomal loss of heterozygosity than do other thyroid cancers, and it harbors unique mitochondrial DNA variations. Clinically, oncocytic thyroid carcinoma is more likely to have locoregional (lymph node) metastases than is follicular thyroid carcinoma-with which it was formerly classified-and it develops distant metastases more frequently than papillary thyroid carcinoma. In addition, oncocytic thyroid carcinoma rarely absorbs radioiodine.

Conclusions and Relevance

The findings of this review suggest that the distinct clinical presentation of oncocytic thyroid carcinoma, including its metastatic behavior and its reduced avidity to radioiodine therapy, warrants a tailored disease management approach. The reclassification of oncocytic thyroid carcinoma by the World Health Organization is an important milestone toward developing a specific and comprehensive clinical management for oncocytic thyroid carcinoma that considers its distinct characteristics.

The Usefulness of Elastin Staining to Detect Vascular Invasion in Cancer

Tumor prognosis hinges on accurate cancer staging, a pivotal process influenced by the identification of lymphovascular invasion (LVI), i.e., blood vessel and lymphatic vessel invasion. Protocols by the College of American Pathologists (CAP) and the World Health Organization (WHO) have been established to assess LVI in various tumor types, including, but not limited to, breast cancer, colorectal cancer (CRC), pancreatic exocrine tumors, and thyroid carcinomas. The CAP refers to blood vessel invasion as "angioinvasion" (vascular invasion) to differentiate it from lymphatic vessel invasion (lymphatic invasion). For clarity, the latter terms will be used throughout this review. The presence of lymphatic and/or vascular invasion has emerged as a pivotal prognostic factor; therefore, its accurate identification is crucial not only for staging but also for providing the patient with an honest understanding of his/her prognosis. Given the prognostic importance of the correct identification of LVI, specific staining techniques are employed to distinguish lymphatic vessel invasion from angioinvasion and to differentiate true LVI from artifact. These encompass hematoxylin and eosin (H&E) staining, elastic staining, Factor VIII staining, Ulex europaeus I agglutinin staining, CD31, CD34, D2-40, ERG, and D2-40 (podoplanin) immunohistochemical (IHC) stains among others. Based on a review of numerous publications regarding the efficacy of various methods for LVI detection, elastin staining demonstrated superior accuracy and prognostic value, allowing for more targeted treatment strategies. The clinical significance of accurately detecting LVI cannot be overstated, as it is strongly linked to higher cancer-related mortality and an increased risk of tumor recurrence. This review aims to examine the existing literature on the use of elastin stains in the detection of vascular invasion among different types of tumors and its prognostic value.

Large (>4 cm) Intrathyroidal Encapsulated Well-Differentiated Follicular Cell-Derived Carcinoma Without Vascular Invasion May Have Negligible Risk of Recurrence Even When Treated with Lobectomy Alone

Background: Thyroid carcinoma >4 cm in size is staged as T3a. The current American Thyroid Association guidelines recommend subtotal/total thyroidectomy and consideration for postoperative radioactive iodine (RAI) treatment for these tumors. In this retrospective cohort study, we aimed to explore the clinical course of large encapsulated thyroid carcinoma without other risk factors. Methods: Eighty-eight patients with large (>4 cm) encapsulated well-differentiated thyroid carcinoma resected between 1995 and 2021 were included in this retrospective cohort study. Exclusion criteria were tall cell variant, any extent of vascular invasion, extrathyroidal extension (microscopic or gross), high-grade histology, noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), infiltrative tumors, positive resection margin, and cases with follow-up <1 year. The primary outcomes are risk of nodal metastasis at the initial resection, disease-free survival (DFS), and disease-specific survival (DSS). Results: The tumor histotype was follicular carcinoma (n = 18, 21%), oncocytic (Hurthle cell) carcinoma (n = 8, 9%), and papillary thyroid carcinoma (PTC; n = 62, 70%). Among PTC, 38 were encapsulated follicular variant, 20 classic type, and 4 solid variant. Four cases had extensive capsular invasion (CI), 61 (69%) had focal CI, whereas 23 did not have CI. Thirty-two cases (36%) were treated with lobectomy/hemithyroidectomy alone, and 55 patients (62%) did not receive RAI. Five patients had nodal metastasis at the time of primary resection, all of whom had classic-type PTC. The median follow-up period was 4.8 years (interquartile range: 3.2-9.7 years). No recurrence, being local, regional, or distant, was observed in the entire cohort, including those patients treated with lobectomy alone without RAI. The 10-year DFS and DSS were 100%, respectively. Conclusion: Large intrathyroidal encapsulated well-differentiated thyroid carcinoma without vascular invasion follow an extremely indolent clinical course with negligible risk of recurrence. Lobectomy alone without RAI may be the appropriate treatment strategy for this selected group of patients.

Radioactive Iodine Therapy Does not Improve Cancer-specific Survival in Hürthle Cell Carcinoma of the Thyroid

CONTEXT

It is unclear whether radioactive iodine (RAI) therapy could improve cancer-specific survival (CSS) in patients with Hürthle cell carcinoma (HCC) of the thyroid.

OBJECTIVE

To investigate the effect of RAI on CSS in HCC patients.

METHODS

HCC patients who underwent total thyroidectomy (TT) were identified from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2018. The Kaplan-Meier method and the Cox proportional hazards regression model were used to evaluate CSS. Propensity score-matched (PSM) analyses were performed to control the influence of potential confounders.

RESULTS

A total of 2279 patients were identified. RAI treatment was not significantly associated with improved CSS in overall or PSM cohort. Subgroup analyses indicated similar results, even in patients with aggressive features such as age 55 years or older, tumor size greater than 40 mm, distant disease in SEER staging, extrathyroidal extension, and lymph node metastases (all P > .05).

CONCLUSION

RAI has no statistically significant influence on the CSS in HCC patients. This information may aid in decision-making for RAI therapy in these patients.

Mitonuclear genotype remodels the metabolic and microenvironmental landscape of Hürthle cell carcinoma

Hürthle cell carcinomas (HCCs) display two exceptional genotypes: near-homoplasmic mutation of mitochondrial DNA (mtDNA) and genome-wide loss of heterozygosity (gLOH). To understand the phenotypic consequences of these genetic alterations, we analyzed genomic, metabolomic, and immunophenotypic data of HCC and other thyroid cancers. Both mtDNA mutations and profound depletion of citrate pools are common in HCC and other thyroid malignancies, suggesting that thyroid cancers are broadly equipped to survive tricarboxylic acid cycle impairment, whereas metabolites in the reduced form of NADH-dependent lysine degradation pathway were elevated exclusively in HCC. The presence of gLOH was not associated with metabolic phenotypes but rather with reduced immune infiltration, indicating that gLOH confers a selective advantage partially through immunosuppression. Unsupervised multimodal clustering revealed four clusters of HCC with distinct clinical, metabolomic, and microenvironmental phenotypes but overlapping genotypes. These findings chart the metabolic and microenvironmental landscape of HCC and shed light on the interaction between genotype, metabolism, and the microenvironment in cancer.

Follicular and Hurthle Cell Carcinoma: Comparison of Clinicopathological Features and Clinical Outcomes

Background: Follicular thyroid carcinoma (FTC) and Hurthle cell carcinoma (HCC) are rare and aggressive thyroid cancers with limited published data comparing their outcomes or regarding their subtypes. The aim of this study was to describe clinicopathological features and compare clinical outcomes of patients with FTC and HCC based on the 2017 World Health Organization definition and extent of vascular invasion (VI). Methods: We retrospectively studied 190 patients with HCC and FTC primarily treated with surgery at Memorial Sloan Kettering Cancer Center between 1986 and 2015. Patients were classified as minimally invasive (MI), encapsulated angioinvasive with focal VI (EA-FVI), encapsulated angioinvasive with extensive VI (EA-EVI), and as widely invasive (WI). To compare clinical outcomes, patients were grouped as follows: group 1 = FTC-MI and FTC EA-FVI, group 2 = FTC EA-EVI and FTC-WI, group 3 = HCC-MI and HCC EA-FVI, group 4 = HCC EA-EVI and HCC-WI. Outcomes of interest were overall survival (OS), disease-specific survival (DSS), recurrence-free survival (RFS), locoregional recurrence-free survival (LRRFS), and distant recurrence-free survival (DRFS). Outcomes were determined using the Kaplan-Meier method and compared with log-rank test. Results: Patients with HCC (n = 111) were more likely to be older than 55 years old (59% vs. 27%, p < 0.001) with a tendency to present with more extensive VI (33% vs. 19%, p = 0.07) compared with FTC (n = 79). Comparing groups 1, 2, 3, and 4, group 4 patients were more likely to recur (DFS 98%, 93%, 98% vs. 73%, respectively, p = 0.0069). There was no statistically significant difference in OS, DSS LRRFS, or DRFS. Stratified by extent of VI (no, focal, and extensive VI), patients with extensive VI were more likely to recur (RFS 100%, 95%, 77%, p = 0.0025) and had poorer distant control (DRFS: 100%, 95%, 80%, p = 0.022), compared with patients absent or focal VI. Conclusions: Accurate assessment of the extent of VI and tumor phenotype (follicular vs. Hurthle) are essential in identifying patients at higher risk of recurrence.

Clinical impact of follicular oncocytic (Hürthle cell) carcinoma in comparison with corresponding classical follicular thyroid carcinoma

PURPOSE

There are controversial debates if patients with Hürthle cell carcinoma, also known as oxyphilic or oncocytic cell follicular thyroid carcinoma, have a poorer outcome. In this study, we systematically evaluated the clinical outcome in a large patient cohort following thyroidectomy and initial I-131 radioactive iodine therapy (RIT).

METHODS

We retrospectively evaluated a total of 378 patients with diagnosed oncocytic follicular Hürthle cell carcinoma (OFTC) (N = 126) or with classical follicular thyroid carcinoma (FTC) (N = 252). Patients received thyroidectomy and complementary I-131 RIT. Clinical data regarding basic demographic characteristics, tumor grade, persistent disease and recurrence during follow-up, and disease-free, disease-specific, and overall survival were collected during follow-up of 6.9 years (interquartile range 3.7; 11.7 years). Univariate and multivariate analyses were used to identify factors associated with disease-related and overall survival.

RESULTS

Before and after matching for risk factors, recurrence was significantly more frequently diagnosed in OFTC patients during follow-up (17% vs. 8%; p value 0.037). Likewise, OFTC patients presented with a reduced mean disease-free survival of 17.9 years (95% CI 16.0-19.8) vs. 20.1 years (95% CI 19.0-21.1) in FTC patients (p value 0.027). Multivariate analysis revealed OFTC (HR 0.502; 95% CI 0.309-0.816) as the only independent prognostic factor for disease-free survival. Distant metastases of OFTC patients were significantly less iodine-avid (p value 0.014). Mean disease-specific and overall survival did not differ significantly (p value 0.671 and 0.687) during follow-up of median 6.9 years (3.7; 11.7 years).

CONCLUSIONS

Our study suggests that recurrence is more often seen in OFTC patients. OFTC patients have a poorer prognosis for disease-free survival. Thus, OFTC and FTC behave differently and should be categorized separately. However, patients suffering from OFTC present with the same overall and disease-specific survival at the end of follow-up indifferent to FTC patients after initial RIT.

Clinical characteristics and prognostic factors of Hurthle cell carcinoma: a population based study

Background

Thyroid Hurthle cell carcinoma (HCC) is a rare disease with high risk of invasion and metastasis and poor prognosis. The clinical characteristics, prognosis and treatment of HCC are still controversial, and clinical data are still limited to some case reports. Therefore, understanding the characteristics and survival factors of HCC is clinically necessary.

Methods

This study collected data from HCC patients diagnosed pathologically from 2004 to 2015, including basic population characteristics, tumor characteristics, and epidemiological and survival data. The data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database to conduct a population cohort study.

Results

A total of 2101 HCC patients with an average age of 55.42 ± 15.27 years were enrolled in this study. Of them, 1740 (82.82%) patients had local disease, 245 (11.66%) had regional disease, and 89 (4.24%) had distant disease. Total thyroidectomy was performed in 1669 (79.44%) patients, partial thyroidectomy was performed in 382 (18.18%) patients, and radioactive iodine (RAI) was used in 1155 (54.97%) patients. The 5-year and 10-year cancer-specific survival rate was 95.4 and 92.6%, respectively. The distant disease group had significantly more male patients, multifocal tumors, and extensive tumors compared to the local disease group. Multivariate survival analysis showed that age (P < 0.05), SEER stage (P < 0.001), and T-stage (P = 0.001) had significant effects on survival. There was no significant difference in survival between total and partial thyroidectomy (P = 0.078), or between RAI and non-RAI (P = 0.733).

Conclusion

Male gender, multifocal tumors, and extended tumors are associated with increased risk of late stage HCC. Age over 45 years, distant SEER stage, and late T-stage are independent risk factors for mortality in HCC.

Hürthle-cell neoplasms of the thyroid: An algorithmic approach to pathologic diagnosis in light of molecular advances

Our understanding of neoplasia is evolving at a rapid pace in these exciting times, where recent molecular pathology advances are reinforcing and fine tuning morphological divisions and classification. Thyroid gland neoplasia in general, and Hürthle-cell neoplasms in particular, are no exception in the current era of histopathology-molecular biology paradigm. In this review paper, we discuss the rationale that led pathologists in the past to separate Hürthle-cell neoplasms into its own dedicated diagnostic category, and provide an algorithmic approach to the differential diagnosis of oncocytic lesions of the thyroid. This review will also shed light on the current WHO classification of Hürthle-cell neoplasms in light of molecular advances that justify histopathologic distinctions.

METASTATIC HÜRTHLE CELL CARCINOMA PRESENTING WITH LOW FREE THYROXINE, SEVERE HYPERCALCEMIA AND SPURIOUS GROWTH HORMONE PRODUCTION

Objective

Hürthle cell tumors constitute about 5% of thyroid neoplasms. They have malignant potential, behaving very aggressively compared to other differentiated thyroid cancers. The objective of this case report is to describe a case of a Hürthle cell carcinoma with a single large metastasis in the liver presenting almost 17 years after hemithyroidectomy. We highlight the difficulties in making a histologic diagnosis and the unpredictable nature of this cancer.

Methods

The patient history and biochemistry were detailed. Thyroid function tests analyzed on multiple platforms (single-photon emission computed tomography, dynamic magnetic resonance imaging, technetium-99m bone scan, and radioactive iodine) were used to aid biochemical and radiologic diagnosis.

Results

The patient's thyroid function test showed persistently low free thyroxine concentrations with normal thyroid stimulating hormone and free triiodothyronine, suggesting rapid deiodination in the context of a large liver lesion. Radiologic and morphologic appearances of the liver lesion led to an initial misdiagnosis of primary hepato-cellular carcinoma, revised to metastatic Hürthle cell carcinoma after positive immunochemistry. Nonparathyroid hormone-related intractable hypercalcemia of malignancy with an unusual pattern of elevated 1,25-dihydroxyvitamin D and raised fibroblast growth factor 23 concentrations culminated in his demise.

Conclusions

In Hürthle cell carcinomas treated with partial thyroidectomy, subsequent abnormal thyroid functions tests may herald a more sinister underlying diagnosis. The management of Hürthle cell carcinoma relies heavily on the initial histology results. Histologic diagnosis should be sought earlier in abnormal and suspicious distant masses. Malignant hypercalcemia poses a great challenge in delayed presentations and can prove resistant to conventional treatments.

Hürthle Cell Carcinoma: Clinic-Pathological and Biological Aspects

Despite its structural simplicity the thyroid gland can give rise to a wide variety of tumor types.

Although a substantial amount of work has been done in the past twenty-five years to redefine the clinic-pathological features of most types of thyroid tumors of follicular cell origin, some aspects of thyroid tumors composed of oncocytes, generally known as Hürthle cell tumors, are still matter of discussion. The major issues concern their very existence as a bona fide tumor type, the occurrence of benign and malignant forms and their relative frequency, the predictive value of morphologic parameters, the natural history of the malignant forms and the classification of Hürthle cell tumors with a papillary growth pattern. The definition of oncocytic cell, oncocytic neoplasm and oncocytic carcinoma as well as the pathologic characteristics and clinical behavior of neoplasms composed of oncocytes will be discussed.

The contribution of molecular pathology to the classification of thyroid tumors

Significant molecular advances have been undertaken for the past two decades in the field of thyroid follicular neoplasms, including a detailed genomic profile of papillary thyroid carcinoma (PTC) by The Cancer Genome Atlas (TCGA) project. These molecular discoveries led to a better understanding of the pathogenesis of thyroid neoplasms and resulted in reclassification of certain types of thyroid tumors. This review discusses how, 1) the molecular profiles of follicular-patterned lesions led to the reclassification of the follicular variant of PTC into non-invasive follicular thyroid neoplasm with papillary like nuclei, 2) the genotyping of Hürthle cell neoplasm provided the rationale to classify these tumors independently from follicular adenomas and carcinomas, and 3) BRAF and RAS molecular signatures have the potential of subclassifying PTC and poorly differentiated thyroid carcinoma into clinically relevant molecular subtypes.

Propensity score matching analysis of the prognosis for the rare oxyphilic subtype of thyroid cancer (Hurthle cell carcinoma)

There is controversy regarding the prognosis of patients with oxyphilic thyroid cancer (OXTC). The present study compared the prognoses of OXTC, papillary thyroid cancer (PTC), and follicular thyroid cancer (FTC), in order to provide a new perspective regarding the treatment guidelines for these diseases. We evaluated data from patients with thyroid cancer who were included in the Surveillance, Epidemiology, and End Results database between 2004 and 2013. Patient mortality was evaluated using Cox proportional hazards regression analyses and Kaplan-Meier analyses with log-rank tests. The multivariate Cox regression analysis revealed that the cancer-specific survival rate for OXTC was similar to that for PTC, but higher than that for FTC. However, after propensity score matching for relevant factors, the cancer-specific survival rate for OXTC was higher than that for PTC and FTC. This unexpected result provides new implications for the treatment of patients with OXTC.

A Unique Case of Bilateral Hürthle Cell Adenoma in an Adolescent

BACKGROUND

Hürthle cell (HC) neoplasms are rare among pediatric thyroid cancers. HC adenomas (HCA) are typically benign and localized unilaterally without recurrence, and they are thus treated by hemithyroidectomy. HC carcinomas (HCC) can be bilateral and are more aggressive, necessitating total thyroidectomy. Diagnosis relies upon surgical histopathology demonstrating invasion for classification as HCC or lack of invasion in HCA, since fine needle aspiration fails to differentiate between the two.

METHODS

We report a case of a 14-year-old adolescent female with bilateral HCA. She had an initial left hemithyroidectomy for a large nodule measuring 2 × 1.5 × 1.2 cm3 in the left lobe, while smaller subcentimeter nodules remained under surveillance in the right. One year later, a nodule in the right lobe doubled in size, necessitating a right hemithyroidectomy which also revealed HCA.

CONCLUSION

To our knowledge, this is the first reported case of bilateral HCA in pediatrics. It highlights the importance of close surveillance of persistent small nodules, even in patients with previously documented benign lesions such as HCA, which are typically thought to be unilateral and localized. Both HCA and HCC remain unpredictable in behavior, and treatment of HCA should be individualized.

Survival and prognostic factors for survival, cancer specific survival and disease free interval in 239 patients with Hurthle cell carcinoma: a single center experience

BACKGROUND

Hurthle cell carcinoma makes up 3 to 5% of all thyroid cancers and is considered to be a true rarity. The aim of our study was to analyze clinical characteristics and survival rates of patients with Hurthle cell carcinoma.

METHODS

Clinical data regarding basic demographic characteristics, tumor grade, type of surgical treatment and vital status were collected. Methods of descriptive statistics and Kaplan-Meier survival curves were used for statistical analysis. Cox proportional hazards regression was used to identify independent predictors.

RESULTS

During the period from 1995 to 2014, 239 patients with Hurthle cell carcinoma were treated at our Institution. The average age of the patients was 54.3, with female to male ratio of 3.6:1 and average tumor size was 41.8 mm. The overall recurrence rate was 12.1%, with average time for relapse of 90.74 months and average time without any signs of the disease of 222.4 months. Overall 5-year, 10-year and 20-year survival rates were 89.4%, 77.2%, 61.9% respectively. The 5-year, 10-year and 20-year cancer specific survival rates were 94.6%, 92.5%, 87.4%, respectively. When disease free interval was observed, 5-year, 10-year and 20-year rates were 91.1%, 86.2%, 68.5%, respectively. The affection of both thyroid lobes and the need for reoperation due to local relapse were unfavorable independent prognostic factors, while total thyroidectomy as primary procedure was favorable predictive factor for cancer specific survival.

CONCLUSION

Hurthle cell carcinoma is a rare tumor with an encouraging prognosis and after adequate surgical treatment recurrences are rare.

Evolution of the histologic classification of thyroid neoplasms and its impact on clinical management

The vast majority of low grade follicular cell derived thyroid carcinomas follows an indolent clinical course and is associated with very low mortality. Risk stratification using multiple clinical and pathologic characteristics has become the standard of care to guide appropriate management and avoid overtreatment. Over the past few decades, the field of thyroid pathology has witnessed several major changes that significantly impacted upon patients' care. These are: 1) The reclassification of non-invasive encapsulated follicular variant of papillary thyroid carcinoma as noninvasive follicular thyroid neoplasm with papillary-like nuclear features; 2) the diagnosis of Hurthle cell carcinoma based on the presence of capsular and vascular invasion; 3) a detailed definition of poorly differentiated thyroid carcinoma, taking into consideration mitosis and necrosis; and 4) the emphasis on a detailed pathologic analysis such as the extent of vascular invasion and extrathyroidal extension. This review describes these histological concepts and details the history, rationale, and clinical impacts of such changes. These shifts in the classification and characterization of thyroid carcinoma provided a platform supporting therapy de-escalation. In addition several lessons were learned from these changes especially from the misclassification of the non-invasive encapsulated follicular variant of papillary thyroid carcinoma. We hope that the lessons learned will help better classify tumors in the future whether arising in the thyroid or other organs.

18F-Fluorodeoxyglucose-Positron Emission Tomography/Computed Tomography for Other Thyroid Cancers: Medullary, Anaplastic, Lymphoma and So Forth

Positron emission tomography/computed tomography (PET/CT) with ¹⁸F-fluorodeoxyglucose (FDG) is used in staging, restaging, and evaluation of therapy response in many cancers as well as differentiated thyroid carcinomas especially in non-iodine avid variants. Its potential in less frequent thyroid tumors like medullary, anaplastic thyroid cancers, thyroid lymphoma and metastatic tumors of the thyroid however, is not well established yet. The aim of this review is to provide an overview on the recent applications and indications of ¹⁸F-FDG PET/CT in these tumors and to focus on the controversies in the clinical setting.

Treatment and outcome of 32 patients with distant metastases of Hürthle cell thyroid carcinoma: a single-institution experience

Background

It is generally believed that patients with Hürthle cell thyroid carcinoma (HCTC) have a poor prognosis. Furthermore, distant metastases represent the most frequent cause of thyroid cancer-related death of patients with HCTC. The aim of this study was to report the treatment and outcomes of patients with distant metastases.

Methods

Altogether 108 patients were treated for HCTC from 1972 to 2011 in our tertiary center and 32 patients (19 females, 13 males; median age 64.5 years) had either initially proven metastatic disease (N = 12) or distant progression of HCTC after initial treatment (N = 20). Patients with metastases were followed for 1–226 (median 77) months. Data were collected on the patients’ gender and age, extent of their disease, morphologic characteristics, therapy, outcome, and survival rate. Statistical correlation between possible prognostic factors and cause-specific survival from time of detection of metastases was analyzed by univariate analysis and log-rank test.

Results

The most common were lung metastases, followed by bone, mediastinum, kidney, and liver in 24, 8, 2, 1, and 1 case, respectively. Total thyroidectomy, lobectomy, subtotal thyroidectomy and neck dissection were performed in 19, 10, 3, and 7 patients, respectively. Radioiodine (RAI) ablation of thyroid remnant was performed in 30 patients, while 20 of them had RAI therapy (median 4 times). RAI uptake in metastases was present in 16 patients and ranged from 0.05 % to 12 %. Chemotherapy was used in 13 patients and external beam radiotherapy in 19 patients. Locoregional control of disease was achieved in 19/21 (90 %) cases who succumbed due to HCTC. Estimated 10-year disease-specific survival for all patients was 60 %. 10-year disease-specific survival for patients with pulmonary metastases and other sites metastases was 60 % and 62 %, respectively. 10-year disease-specific survival for patients with single organ and multiple organ metastases was 52 %, and 100 %, respectively. Estimated median disease-specific survival after the diagnosis of metastatic disease for all patients was 77 months. The median disease-specific survival after the diagnosis of metastatic disease for patients with pulmonary metastases and other sites metastases was 72 and 138 months, respectively.

Conclusions

Ten-year disease-specific survival for all patients with metastatic Hürthle cell thyroid carcinoma, patients with pulmonary metastases and bone metastases was 60 %, 60 % and 68 %, respectively.

Hurthle Cell Lesion: Controversies, Challenges, and Debates

Hurthle cell lesion is one of the most questionable clinico-pathological entities in most of its aspects. Literature has used the terms oncocytic, oxyphilic, Hurthle, and Ashkanazy interchangeably; what does each term denote? Who first described these cells? What is the cell of origin? How much Hurthle cells should be present to define the lesion as Hurthle cell one? Is it possible to differentiate hyperplastic from neoplastic and benign from malignant Hurthle cell lesion on a non-histopathologic ground? Does it belong to follicular or to papillary neoplasms or should it be classified separately? Can we anticipate its clinical behavior or predict its outcome? How can we manage? We will try to answer these questions in light of the ongoing relevant arguments with the aim of resolving some uncertainties and suggesting how to solve others.

Expression of miRNA and Occurrence of Distant Metastases in Patients with Hürthle Cell Carcinoma

Background. Hürthle cell thyroid carcinoma (HCTC) is a rare type of thyroid carcinoma. In the present study, we investigated whether the expression of miRNAs of interest is associated with the occurrence of metastases in patients with HCTC. Materials and Methods. In 39 patients with HCTC (22 with nonmetastatic and 17 with regional or distant metastatic disease), the expression levels of six miRNAs (miR-138, miR-183, miR-221, miR-222, miR-768-3p, and miR-885-5p) and U6 snRNA as endogenous control were determined in FFPE samples of primary tumor and normal thyroid tissue using TaqMan miRNA assays. Results. In patients with HCTC, miR-138 and miR-768-3p were downregulated in tumor samples compared to normal tissue (p = 0.013 and p = 0.010, resp.). These two miRNAs were also significantly downregulated in tumor samples of patients with metastatic disease (p = 0.030 and p = 0.048, resp.) but not in patients with nonmetastatic disease (p = 0.249 and p = 0.101, resp.). In patients with nonmetastatic disease, miR-221 and miR-885-5p were slightly, albeit significantly, upregulated in tumorous compared to normal tissue (p = 0.042 and p = 0.027, resp.). Conclusion. Expression of miRNA (miR-183, miR-221, and miR-885-5p) in tumor tissue is associated with the occurrence of distant metastases in patients with HCTC.

Encapsulated Thyroid Carcinoma of Follicular Cell Origin

Encapsulated carcinomas of follicular cell origin are subject to considerable controversies. This group includes an encapsulated/well-circumscribed (E/WC) follicular variant of papillary carcinoma (FVPTC) and encapsulated follicular and Hurthle cell carcinoma (EFC, EHC respectively). FVPTC usually presents as an E/WC tumor and less commonly as an infiltrative neoplasm. E/WC FVPTC rarely metastasizes to lymph nodes, whereas infiltrative tumors often present with cervical nodal metastases. Many studies revealed FVPTC in general to be genetically close to the follicular adenomas (FA)/EFC group of tumors. This is particularly true for the E/WC FVPTC which has a high rate of RAS and lack BRAFV600E mutations. Infiltrative FVPTC has an opposite molecular profile closer to classical papillary carcinoma than to FA/EFC (BRAFV600E > RAS mutations). Noninvasive E/WC FVPTCs are extremely indolent even if treated with lobectomy alone. While EFC and EHC with capsular invasion only have an excellent outcome, those with extensive (≥4 foci) lymphovascular invasion (LVI) have a significant rate of distant recurrence. The prognosis of those with focal LVI seems good, but more studies are needed to confirm their behavior. In EHC, those with extensive/significant LVI have a different RNA expression profile than those with less LVI. EHC appear to recur earlier, are less RAI avid, and have a different mutation profile than EFC. Noninvasive E/WC FVPTC should be treated conservatively. There is therefore a need to reclassify the E/WC FVPTC in order to prevent overtreatment. In view of their molecular and behavioral differences, EHC should not be considered a subset of EFC.

Papillary Thyroid Carcinoma Metastasis to the Lumbar Spine Masquerading as a Schmorl's Node

A Schmorl's node is a common incidental finding encountered during radiologic imaging. Despite the vertebral body being a common site of metastatic disease, a lytic lesion adjacent to an endplate with typical imaging features can often confidently be called a Schmorl's node. This is a case report of a patient with a single well-defined FDG-avid papillary thyroid carcinoma metastasis to the spine that had imaging findings characteristic of a Schmorl's node on CT and MRI. This case is important to consider as it demonstrates that the imaging characteristics of metastatic disease and Schmorl's nodes can overlap.

Oncocytic adenomas of thyroid-mimicking benign or metastatic disease on 18F-FDG-PET scan

BACKGROUND

The literature is sparse concerning 18F-fluorodeoxyglucose (18F-FDG) accumulation in the Hürthle cell neoplasm (HCN) of the thyroid. Given the difficulty of accurately diagnosing HCN, even with ultrasound (US) and fine needle aspiration biopsy (FNAB), the ability to accurately characterize these lesions by 18F-FDG positron emission tomography (PET) would be of value.

PURPOSE

To describe six cases of oncocytic proliferation in the thyroid gland that mimics the presence of metastatic disease and was detected incidentally by an 18F-FDG PET scan.

MATERIAL AND METHODS

We conducted whole-body 18F-FDG PET examinations for cancer staging in 1862 oncological patients from 2012 to 2013. Among them, six subjects (4 women, 2 men; age range, 45-85 years) with focal-enhanced 18F-FDG accumulation in the thyroid gland were selected from the study population. This study group was further investigated using 99 m-Tc-pertechnetate scintigraphy, US, and FNAB. Two experienced nuclear physicians reviewed the images. Gray-scale US and color Doppler (CD) sonographic examinations of the thyroid were undertaken for all subjects using a sonographic device Logiq 5 Expert (GE Medical Systems, Osaka, Japan) equipped with a 7-12 MHz linear array transducer.

RESULTS

In all six cases, abnormal 18F-FDG uptake was found locally in the thyroid. The average SUVmax of the HCN was 5.8 (range, 2.6-16). In all six cases, 99 m-Tc-pertechnetate scintigraphy showed a cold spot. Compared with normal parenchymal vascularity, five of the six masses were shown to be hypervascular by CD ultrasonography.

CONCLUSION

On PET scans, oncocytic proliferations of the thyroid may mimic metastases of other malignancies. The focal-enhanced uptake of 18F-FDG PET may be associated with a focal increase in the metabolic activity of the thyroid parenchyma due to the presence of oncocytes. Our study emphasizes the importance of obtaining cytological evidence before making a diagnosis of metastatic disease.

Prognostic value of vascular invasion in well-differentiated papillary thyroid carcinoma

BACKGROUND

Vascular invasion (VI) is an important predictor of distant metastasis and possible radioactive iodine (RAI) benefit in follicular, Hürthle cell, and poorly differentiated thyroid carcinomas, but its role in well-differentiated papillary thyroid cancer (WDTC) remains unclear.

METHODS

Archived pathological material of all differentiated thyroid carcinoma patients undergoing primary surgical treatment at Memorial Sloan-Kettering Cancer Center between 1986 and 2003 was reviewed by two dedicated thyroid pathologists. Only WDTCs were included in the present study. Standard statistical methods were used to assess the relationship between VI and outcomes of interest, including 10-year disease-specific survival (DSS), regional recurrence-free survival (RRFS), and distant recurrence-free survival (DRFS).

RESULTS

VI was present in 47 of 698 WDTC (6.7%). VI was significantly associated with tumor size >4.0 cm, extrathyroidal extension, distant metastasis, and RAI treatment. On univariate analysis, VI was predictive of decreased 10-year DRFS, but not DSS or RRFS. On multivariate analysis, VI was not an independent predictor of DRFS. Univariate survival analysis of 422 RAI-naïve WDTC showed that both size >4 cm and VI were predictors of outcome, but only size remained independently predictive on multivariate analysis.

CONCLUSION

The presence of VI is not an independent predictor of outcome in WDTC.

Appearance of Hürthle cell carcinoma soon after surgical extirpation of Hürthle cell adenoma and follicular adenoma of the thyroid gland

BACKGROUND

Hürthle cell neoplasms could be benign (Hürthle cell adenoma) or malignant (Hürthle cell carcinoma). Hürthle cell carcinoma is a rare tumour, representing 5% of all differentiated thyroid carcinomas. The cytological evaluation of Hürthle cell neoplasms by fine needle aspiration biopsy (FNAB) is complicated because of the presence of Hürthle cells in both Hürthle cell adenoma and Hürthle cell carcinoma. Thus, the preoperative distinction between these two entities is very difficult and possible only with pathohistological findings of the removed tumour.

CASE REPORT

A 57-year old female patient was admitted at our Department, for investigation of nodular thyroid gland. She was euthyroid and FNAB of the nodules in both thyroid lobes were consistent of Hürthle cell adenoma with cellular atypias. After thyroidectomy the histopathology revealed Hürthle cell adenoma with high cellular content and discrete cellular atypias in the left lobe and follicular thyroid adenoma without cellular atypias in the right lobe. One year after substitution therapy, a palpable tumour on the left side of the remnant tissue was found, significantly growing with time, presented as hot nodule on (99m)Tc-sestamibi scan and conclusive with Hürthle cell adenoma with marked cellularity on FNAB. Tumorectomy was performed and well-differentiated Hürthle cell carcinoma detected. The patient received ablative dose of 100 mCi (131)I. No signs of metastatic disease are present up to date.

CONCLUSIONS

The differences between Hürthle cell adenomas and Hürthle cell carcinomas could be clearly made only by histopathological evaluation. Patients with cytological diagnosis of Hürthle cell neoplasms should proceed to total thyroidectomy, especially if tumour size is > 1cm, FNAB findings comprise cellular atypias and/or multiple bilateral nodules are detected in the thyroid gland.

Clinical and molecular features of Hürthle cell carcinoma of the thyroid

CONTEXT

Hürthle cell cancer (HCC) of the thyroid remains the subject of controversy with respect to natural course, treatment, and follow-up.

OBJECTIVE

The objective of the study was to evaluate the clinical and molecular features associated with outcome in HCC.

DESIGN

The study was a review of 173 HCC cases treated at Mayo Clinic over 11 years with a median 5.8-year follow-up.

RESULTS

None of the patients with minimally invasive histology had persistent disease, clinical recurrence, or disease-related death. Male gender and TNM stage were independently associated with increased risk of clinical recurrence or death in widely invasive patients. The 5-year cumulative probability of clinical recurrence or death was higher in patients with TNM stage III-IV (females, 74%; males, 91%) compared with patients with TNM stage I-II (females, 0%; males, 17%). Pulmonary metastases were best identified by computed tomography, whereas radioactive iodine scans were positive in only two of 27 cases. Thyroglobulin was detectable in patients with clinical disease, with the notable exception of five patients with distant metastases. The common TERT C228T promoter mutation was detected in both widely invasive and minimally invasive tumors. TERT mRNA was below the limit of detection in all samples.

CONCLUSION

Widely invasive HCC with TNM stage III-IV is aggressive, with low probability of recurrence-free survival. Males have worse outcomes than females. Minimally invasive HCC appears to be considerably less aggressive. Radioactive iodine scan performs poorly in detecting distant disease. Although the TERT gene is mutated in HCC, the role of this mutation remains to be demonstrated.

Prognostic factors for disease-specific survival in 108 patients with Hürthle cell thyroid carcinoma: a single-institution experience

BACKGROUND

Hürthle cell thyroid carcinoma (HCTC) is a rare disease. It is believed that it is more aggressive than follicular thyroid carcinoma. The aim of our study was to identify factors associated with disease-specific and disease-free survival.

METHODS

Altogether, 108 patients with HCTC (26 male, 82 female; median age 62 years; range 19-87 years) treated at our Institute from 1972 to 2011 were included in the present retrospective study. Data on age, clinical and histopathological factors, tumor stage, recurrence, disease-free and disease-specific survival were collected. Univariate analysis was used to identify factors associated with disease-specific survival. Cox's multivariate regression model was used to identify independent prognostic factors for disease-specific survival.

RESULTS

The follow-up period was 1 to 337 (median 105) months. Of 108 patients, 12 (11%) had distant and 8 (7%) had locoregional metastases before primary treatment. Recurrence was diagnosed in 26 cases (24%): locoregional, distant, and both locoregional and distant in 12, 11, and 3 cases, respectively. The 5-year, 10-year, and 20-year disease-specific survival were 96%, 88%, and 67%, respectively. Independent prognostic factors for disease-specific survival were: age of patients at diagnosis, distant metastases and residual tumor after surgery.

CONCLUSION

Long disease-specific survival was found in patients with HCTC younger than 45 years of age without distant metastases and without residual tumor after surgery.

PET/CT in the management of thyroid cancers

OBJECTIVE

Thyroid cancer is the most common endocrine cancer. This review evaluates the established use of (18)F-FDG PET/CT in papillary, follicular, Hürthle cell, anaplastic, and medullary thyroid cancers. The significance of incidental diffuse and focal thyroid FDG uptake is discussed. The evolving value of non-FDG radiotracers, including (124)I, (18)F-dihydroxyphenylalanine, and (68)Ga somatostatin analogs, is summarized.

CONCLUSION

PET/CT is a valuable imaging test, in the appropriate clinical context, for the management of thyroid cancers.

Hürthle cells in fine-needle aspirates of the thyroid: a review of their diagnostic criteria and significance

Although the cytological assessment of Hürthle cell lesions is challenging, the literature offers good, albeit imperfect, guidance to aid in the crucial distinction between nonneoplastic and neoplastic lesions. The significance of a cytologic diagnosis of follicular neoplasm, Hürthle cell type, lies in the rate of malignancy on follow-up surgical excision, ranging in the literature from 10% to 45%. A cytodiagnosis of atypia of undetermined significance (AUS), Hürthle cell type, appears to be associated with a lower risk of malignancy on follow-up than other subtypes of AUS; however, this area warrants further investigation.

The role of fluorine-18-fluorodeoxyglucose positron emission tomography in aggressive histological subtypes of thyroid cancer: an overview

Aggressive histological subtypes of thyroid cancer are rare and have a poor prognosis. The most important aggressive subtypes of thyroid cancer are Hürthle cell carcinoma (HCTC) and anaplastic and poorly differentiated carcinoma (ATC and PDTC). The American Thyroid Association recently published guidelines for the management of patients with ATC, but no specific guidelines have been done about HCTC. We performed an overview of the literature about the role of Fluorine-18-Fluorodeoxyglucose positron emission tomography or positron emission tomography/computed tomography (FDG-PET or PET/CT) in aggressive histological subtypes of thyroid cancer. Only few original studies about the role of FDG-PET or PET/CT in HCTC, PDTC, and ATC have been published in the literature. FDG-PET or PET/CT seems to be useful in staging or followup of invasive and metastatic HCTC. FDG-PET or PET/CT should be used in patients with ATC in initial staging and in the followup after surgery to evaluate metastatic disease. Some authors suggest the use of FDG-PET/CT in staging of PDTC, but more studies are needed to define the diagnostic use of FDG-PET/CT in this setting. Limited experience suggests the usefulness of FDG-PET or PET/CT in patients with more aggressive histological subtypes of DTC. However, DTC presenting as radioiodine refractory and FDG-PET positive should be considered aggressive tumours with poor prognosis.

The oncocyte that went places: diagnosis with EUS-guided FNA

Although uncommon, Hurthle cell neoplasms have a characteristic histologic and cytologic features which often aid in the diagnosis of these lesions. In fine needle aspiration biopsies, determining malignant potential on cytologic features is challenging unless other evidence of malignancy (such as metastases) are known. The role of EUS-guided FNA in diagnosing superior mediastinal masses has been described previously. It's role in evaluating subcarinal metastases from lung cancer primaries have also heen studied. However we describe metastatic thyroid Hurthle cell carcinoma to the subcarina diagnosed through EUS-guided FNA combining the unique cytologic features o Hurthle cell neoplasms and the versatility ofthe endoscopic ultrasound to reach a diagnosis in this unusual neoplasm.

Encapsulated malignant follicular cell-derived thyroid tumors

Encapsulated malignant follicular cell-derived thyroid tumors are subject to considerable controversies. This group includes encapsulated follicular variant of papillary carcinoma (FVPTC) and encapsulated (so-called minimally invasive) follicular carcinoma (EFC). FVPTC usually presents as an encapsulated tumor and less commonly as a partially/nonencapsulated infiltrative neoplasm. The encapsulated form rarely metastasizes to lymph node, whereas infiltrative tumors often harbor nodal metastases. Encapsulated FVPTC have a molecular profile very close to follicular adenomas/carcinomas (high rate of RAS and absence of BRAF mutations). Infiltrative follicular variant has an opposite molecular profile closer to classical papillary thyroid carcinoma than to follicular adenoma/carcinoma (BRAF > RAS mutations). Noninvasive encapsulated FVPTC are extremely indolent even if treated with lobectomy without radioactive iodine therapy. Although most EFC are thought to have an excellent outcome, there are cases of EFC that recur and metastasize. EFC with angioinvasion, especially if extensive, have a significant rate of distant recurrence. Encapsulated FVPTC have a molecular profile and a clinical behavior very similar to the follicular adenoma/carcinoma class of tumor. If noninvasive, encapsulated FVPTC should be treated in a very conservative fashion. EFC with angioinvasion, especially if extensive, should not be termed minimally invasive in order to prevent undertreatment of the patient.

Molecular, morphologic, and outcome analysis of thyroid carcinomas according to degree of extrathyroid extension

BACKGROUND

The impact of varying degrees of extrathyroid extension (ETE), especially microscopic ETE (METE), on survival in thyroid carcinomas (TC) has not been well established. Our objective was to analyze ETE at the molecular and histologic levels and assess the effect of its extent on outcome.

METHODS

All cases of TC with ETE but without nodal metastases at presentation (NMP) were identified over a 20-year period and grouped into gross and METE. Twelve papillary thyroid carcinomas (PTCs) without ETE and NMP were also analyzed. Cases with paraffin tissues were subjected to mass spectrometry genotyping encompassing the most significant oncogenes in TC: 111 mutations in RET, BRAF, NRAS, HRAS, KRAS, PIK3CA, and AKT1, and other related genes were surveyed.

RESULTS

Eighty-one (10%) of 829 patients in the database had ETE and no NMP. There was a much higher frequency of poorly differentiated and anaplastic carcinomas (12/29, 41%) in patients with gross ETE than in those with METE (3/52, 6%) (p < 0.01). There was a higher disease-specific survival (DSS) in patients with METE than in those with gross ETE (p < 0.0001). Except for an anaplastic case, no recurrences were detected in 45 patients with METE, including 23 PTC patients followed up for a median of 10 years without radioactive iodine therapy. Within patients with gross invasion into trachea/esophagus, tumors with high mitotic activity and/or tumor necrosis correlated with worse DSS (p < 0.05). Fifty-six cases with ETE were genotyped as follows: BRAFV600E, 39 (70%); BRAFV600E-AKT1, 1 (1.8%); NRAS, 1 (1.8%); KRAS, 1 (1.8%); RET/PTC, 3 (5%); wild type, 11 (19.6%). Within PTCs, BRAF positivity rate increased the risk of ETE (p = 0.01). If PTC follicular variants are excluded, BRAF positivity does not correlate with ETE status within classical/tall cell PTC.

CONCLUSION

(i) PTCs with METE without NMP have an extremely low recurrence rate in contrast to tumors with gross ETE. (ii) High mitotic activity and/or tumor necrosis confers worse DSS even in patients stratified for gross ETE in trachea/esophagus. (iii) BRAF positivity correlates with the presence of ETE in PTC, but this relationship is lost within classical/tall cell PTC if follicular variants are excluded from the analysis.

Molecular features of thyroid oncocytic tumors

Thyroid oncocytic neoplasms are tumors composed of cells characterized by an aberrant increase of mitochondrial mass. They represent a subset of thyroid tumors whose classification and clinical features has been a matter of controversy for clinicians and pathologists alike. The prevalence of oncocytic tumors in the thyroid gland, the relevance of the issues debated, and the obvious cellular derangement of oncocytic cells, namely a complete deregulation of the mitochondrial mass and metabolism, have spurred many investigators to study the molecular mechanism underlying the genesis of this peculiar cancer phenotype. Their findings, which are unraveling the tumor pathobiology, are the subject of the present review.

Hürthle cell neoplasm: correlation of gray-scale and power Doppler sonographic findings with gross pathology

BACKGROUND

To describe gray-scale and power Doppler (PD) sonographic (US) findings of Hürthle cell neoplasms (HCNs) of the thyroid gland, and to determine if there is any correlation between US and gross pathologic features.

METHOD

This retrospective study included 30 pathologically proven HCNs in 30 subjects who underwent preoperative gray-scale and PD US examinations. The size, shape, margin, echogenicity, echotexture, presence or absence of cystic change, calcifications and halo sign, and vascularity at PD US were evaluated.

RESULT

The longest diameter of HCNs ranged from 12 mm to 63 mm. The shape and margins of the mass were ovoid and smooth, respectively, in all cases. The echogenicity was hypoechoic, isoechoic, hyperechoic, or mixed in 43.3%, 33.3%, 10.0%, and 13.3%, respectively. The echotexture was heterogeneous in 73.3% and homogeneous in 26.7%. Cystic change was present in 56.7% and involved less than 25% of the volume of the mass in 50.0% and 26-50% of the volume in 6.7%. Coarse calcifications were present in 20.0%. Halo sign was present in all cases. The vascularity was combined peri- and intranodular in all cases: predominantly intranodular in 50.0%, predominantly perinodular in 46.7%, and of the "inferno" type in 3.3%. All HCNs were encapsulated on gross pathologic examination.

CONCLUSION

Although many of the US features we observed were nonspecific, HCNs tend to have a halo sign and combined peri- and intranodular vascularity on US, which raises the possibility of an association. The US halo sign corresponds to tumor capsule ongross pathologic examination.

Solitary spinal metastasis of Hürthle cell thyroid carcinoma

Hürthle cell carcinoma is a rare variant of differentiated thyroid cancer that occasionally forms distant metastases. However, even in the presence of metastases, patients with Hürthle cell carcinoma have a relatively good prognosis. There are few reports of Hürthle cell carcinoma metastases to the vertebral column, and none describing aggressive resection of spinal metastases. Here, we report a 68-year-old woman with a solitary metastasis of Hürthle cell carcinoma to the T1 vertebral body causing severe kyphotic deformity, myelopathy, and pain. The patient was treated with aggressive excisional decompression of the spinal cord and T1 vertebral body resection from an entirely posterior approach. Reconstruction and stabilization of the anterior spine was accomplished with a transforaminal lumbar interbody fusion allograft spacer and posterior instrumentation. We discuss aspects of the diagnosis, management, patient selection, and surgical treatment of metastatic Hürthle cell carcinoma in reference to the literature.

Problems and controversies in the histopathology of thyroid carcinomas of follicular cell origin

CONTEXT

Despite past and recent efforts, many problems and controversies remain in the classification of thyroid carcinomas of follicular cell origin. These controversies have an impact on the prognosis and therapy of patients with thyroid carcinoma as well as on the development of robust cutting-edge research aimed at better outcome and quality of life.

OBJECTIVE

To focus on 3 contentious areas with significant clinical value: the follicular variant of papillary thyroid carcinoma, the extent of invasion in follicular carcinoma, and the poorly differentiated thyroid carcinomas.

DATA SOURCES

The published English language literature was reviewed.

CONCLUSIONS

Recent data show that prognosis and therapy for many disease entities can be better delineated if a meticulous microscopic examination is performed. An accurate assessment of the extent of invasion (especially vascular) is crucial. Proliferative grading (ie, mitosis and necrosis) is of high prognostic value and should be looked for in every specimen. In addition, molecular data gathered to date can help reassess these tumors at the histologic level. Classification proposals based on personal experience rather than adequate and careful clinical follow-up should be discouraged.

Update to the College of American Pathologists reporting on thyroid carcinomas

BACKGROUND

The reporting of thyroid carcinomas follows the recommendations of the College of American Pathologists (CAP) protocols and includes papillary carcinoma, follicular carcinoma, anaplastic carcinoma and medullary carcinoma. Despite past and recent efforts, there are a number of controversial issues in the classification and diagnosis of thyroid carcinomas (TC) that, potentially impact on therapy and prognosis of patients with TC.

DISCUSSION

The most updated version of the CAP thyroid cancer protocol incorporates recent changes in histologic classification as well as changes in the staging of thyroid cancers as per the updated American Joint Commission on Cancer staging manual. Among the more contentious issues in the pathology of thyroid carcinoma include the defining criteria for tumor invasiveness. While there are defined criteria for invasion, there is not universal agreement in what constitutes capsular invasion, angioinvasion and extrathyroidal invasion. Irrespective of the discrepant views on invasion, pathologists should report on the presence and extent (focal, widely) of capsular invasion, angioinvasion and extrathyroidal extension. These findings assist clinicians in their assessment of the recurrence risk and potential for metastatic disease. It is beyond the scope of this paper to detail the entire CAP protocol for thyroid carcinomas; rather, this paper addresses some of the more problematic issues confronting pathologists in their assessment and reporting of thyroid carcinomas.

CONCLUSION

The new CAP protocol for reporting of thyroid carcinomas is a step toward improving the clinical value of the histopathologic reporting of TC. Large meticulous clinico-pathologic and molecular studies with long term follow up are still needed in order to increase the impact of microscopic examination on the prognosis and management of TC.

Radioiodine therapy for differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases

BACKGROUND

Differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases has been observed in follow-up studies. The management of this condition remains controversial. Most studies support blind radioactive iodine treatment while others negate this approach.

OBJECTIVES

To assess the effects of radioiodine therapy for differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases.

SEARCH STRATEGY

Studies were obtained from computerised searches of MEDLINE, EMBASE, The Cochrane Library, China National Infrastructure (CNKI) and paper collections of conferences held in Chinese.

SELECTION CRITERIA

Randomised controlled clinical trials and prospective controlled clinical trials.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and interviewed authors of all potentially relevant studies by electronic mail to verify randomisation procedures. One author entered data into a data extraction form and the second one verified the results of this procedure.

MAIN RESULTS

Because of the absence of any suitable randomised or prospective controlled trial in this area, results currently cannot be presented.

AUTHORS' CONCLUSIONS

The currently available evidence is insufficient to reliably assess the potential of radioiodine treatment for differentiated thyroid carcinoma with thyroglobulin positive and radioactive iodine negative metastases.

Oxaliplatin-induced coronary artery spasm: first report of an important side-effect

A 67-year-old woman with metastatic colorectal cancer was given her first oxaliplatin infusion as part of the XELOX protocol. She developed chest pain with ECG changes leading subsequently to a diagnosis of coronary artery spasm. To our knowledge, this is the first report of oxaliplatin-induced coronary artery spasm.