Noninvasive anaplastic thyroid carcinoma: report of a case and literature review

The Incidence Trend and Management of Thyroid Cancer-What Has Changed in the Past Years: Own Experience and Literature Review

Because of ambiguous and widely debated observations concerning the incidence, trend, and management of TC, we performed this analysis. We drew attention to some events, such as "cancer screening activity", introduction of noninvasive follicular neoplasm with papillary-like nuclear features (NIFTP) to TC types, possibility of papillary thyroid microcarcinoma (PTMC) active surveillance (AS), occurrence of personalized medicine in TC management, and, finally, COVID-19 pandemic time. Because of the opinion that all changes have been made mostly by PTC, we compared it to the remaining types of TC in terms of incidence, clinical and pathological characteristics, and treatment. We analyzed patients treated in a single surgical center in eastern Europe (Poland). The prevalence of TC significantly increased from 5.15% in 2008 to 13.84% in 2015, and then significantly decreased to 1.33% in 2022 when the COVID-19 pandemic lasted (p < 0.0001). A similar trend was observed for PTC, when the incidence significantly increased to 13.99% in 2015 and then decreased to 1.38% in 2022 (p < 0.0001). At that time, the NIFTP category was introduced, and observation of PTMC began. The prevalence of FTC and MTC also increased until 2015 and then decreased. Significant differences in age, types of surgery, necessity of reoperation, and pTNM between PTCs and other types of TCs were observed. The average age was significantly lower in PTC patients than in patients with the remaining types of TC (p < 0.0001). Four milestones, including NIFTP introduction, the possibility of PTMC AS, personalized cancer medicine, and the COVID-19 pandemic, may have influenced the general statistics of TC.

Uncommon Site of Metastasis and Prolonged Survival in Patients with Anaplastic Thyroid Carcinoma: A Systematic Review of the Literature

Simple Summary

The therapeutic strategies employed for anaplastic thyroid cancer patients seems to be insufficient to prolong their survival, but some characteristics could predict a good prognosis, so that, starting from our experience we offer a systematic review of the literature to better understand anaplastic thyroid cancers behavior and their prognostic factors, in order to recognize and select the patients with the higher probability of better outcome even if metastatic. Moreover, we described an uncommon site of metastasis in order to improve scientific knowledge about this rare and highly aggressive pathology.

Abstract

Anaplastic thyroid carcinoma (ATC) is a very rare, highly aggressive malignant thyroid tumor with an overall survival from 3 to 5 months in most of the cases. Even the modern and intensive treatments seem not to be enough to provide a cure, also for the resectable ones, and the role of chemotherapy is still unclear but does not seem to prolong survival. Nevertheless, some patients survive longer and have a better outcome, even in the presence of metastasis, than what the literature reports. We present the case of a 64-year-old female affected by ATC, treated on February 2018 with surgery followed by chemoradiation. One year after surgery, the patient developed a subcutaneous recurrence that was radically resected and is still alive 29 months after the diagnosis. We propose a systematic review of the literature to deepen the knowledge of the prognostic factors of ATC with the aim to recognize and select the patients with a better outcome, even if metastatic, and to describe a very uncommon site of metastatization.

Histopathologic Features and Clinical Outcome of Anaplastic Thyroid Carcinoma with a Minor Anaplastic Component

Although prior studies have reported that patients with anaplastic thyroid carcinoma (ATC) with a focal anaplastic component may have a prolonged survival compared to other ATC patients, the outcome data are limited. We evaluated a cohort of ATC resected between 2003 and 2018. Tumor slides were reviewed to confirm the diagnosis and to identify cases with a minor ATC component (defined as comprising < 10% of the tumor). We evaluated the clinical outcome of these patients compared to that of all other cohort patients (characterized as having conventional ATC). Our cohort was composed of 24 cases of ATC that underwent resection, including 8 (33%) with a minor ATC component. Tumors with a minor ATC component were predominantly associated with papillary thyroid carcinoma. For patients with tumors with a minor ATC component, the 1-year and 2-year survival rates and median survival for patients who died of disease were 88%, 43%, and 17 months (range 6-73 months), respectively. In comparison, for patients with conventional ATC, the 1-year and 2-year survival rates and median survival for patients who died of disease were 56%, 44%, and 7 months (range 2-26 months), respectively. There was no difference in 1- and 2-year survival or overall survival by Kaplan-Meier analysis for patients with tumors with a minor ATC component and those with conventional ATC. In conclusion, the difference in overall survival between ATC groups in our cohort was not significant; however, this could be due to the small cohort size or due to characteristics of our group with a minor ATC component; that is, no tumors in this group were limited to the thyroid (stage IVA), resectability with negative margins was infrequent, and 38% of this group had distant metastases at diagnosis (stage IVC).

Anaplastic thyroid carcinoma

Anaplastic thyroid carcinoma (ATC) is a rare but significant malignancy due to its high mortality rate. Rendering an accurate diagnosis is crucial given the prognostic implications and treatment ramifications. Based on the prognostic significance of the extent of invasion of the primary tumor, T staging for ATC changed in the most recent edition of the American Joint Committee on Cancer (AJCC) staging manual. In the past 5 years there has been a rapid increase in our understanding of the molecular basis of ATC which has provided the basis for targeted therapy for some ATC patients. In this review, ATC prognostic factors, histologic and immunotypic features, staging updates, and molecular alterations, with an emphasis on those that may impact treatment, will be discussed.

Angiosarcoma and anaplastic carcinoma of the thyroid are two distinct entities: a morphologic, immunohistochemical, and genetic study

Angiosarcoma and anaplastic carcinoma are the most lethal neoplasms of the thyroid worldwide and share some similarities, which have led to a longstanding controversy on their etiopathological relationship. Thyroid angiosarcomas are characterized by vessel formation and an immunophenotype common to endothelial cells, while anaplastic carcinomas are partially or wholly composed of mesenchymal-like cells that have lost the morphologic and functional features of normal thyroid follicular cells. To investigate whether angiosarcomas represent the endothelial extreme of the differentiation spectrum of carcinomas or they are bona fide vascular neoplasms, we studied the clinico-morphologic and genetic characteristics of a series of 10 angiosarcomas and 22 anaplastic carcinomas. Immunohistochemically, among the endothelial markers, CD31 and ERG were the most consistently expressed in angiosarcomas. Among the markers of thyroid origin, PAX8 was the most reliable in anaplastic carcinomas, while TTF-1 reactivity was found in only 5% of anaplastic carcinomas and thyroglobulin was always negative. Pankeratin reacted with most angiosarcomas and anaplastic carcinomas and is therefore not useful in the differential diagnosis. Interestingly a mutated pattern of p53 immunostaining prompted a diagnosis of anaplastic carcinoma. To compare the genetic profile, we used the NGS approach to sequence hotspot regions within a panel of 57 genes. As a result, only a few mutations were found in angiosarcomas and all of them were single events (no TP53 or TERT mutation). On the other hand, anaplastic carcinomas were characterized by a higher number of mutations, and TP53 and TERT promoter mutations were the most frequent genetic alterations. The lack in angiosarcomas of the common mutations identified in anaplastic carcinomas supports a different genetic origin and strongly suggests that, in spite of a shared sarcomatous morphology and a similar clinical aggressiveness, angiosarcomas and anaplastic carcinomas rely on a completely different set of genetic alterations during their evolution.

Minimally invasive thyroid anaplastic carcinoma with long survival

Anaplastic thyroid carcinoma is a highly lethal malignancy. Previously, only five cases of a noninvasive form of anaplastic thyroid carcinoma with excellent prognosis were reported. We report a case of a 68-year-old man who presented with a 3.8 cm thyroid nodule diagnosed by fine needle aspiration biopsy as poorly differentiated spindled and epithelial malignant cells. Lobectomy and isthmusectomy were performed, and the final diagnosis was microinvasive anaplastic thyroid carcinoma arising in a poorly differentiated carcinoma. The patient remains disease-free after six years, even after hemithyroidectomy and radiation treatment. Noninvasive/microinvasive anaplastic thyroid carcinoma appears to be a different disease entity from classical anaplastic thyroid carcinoma, with favorable prognosis and long disease-free survival.

Heterogeneity of Thyroid Cancer

There are 5 main histological types of thyroid cancers (TCs): papillary, follicular (also known as differentiated), poorly differentiated, anaplastic (the most aggressive form), and medullary TC, and only the latter arises from thyroid C cells. These different forms of TCs show significant variability, both among and within tumours. This great variation is particularly notable among the first 4 types, which all originate from thyroid follicular cells. Importantly, this heterogeneity is not limited to histopathological diversity only but is also manifested as variation in several genetic and/or epigenetic alterations, the numbers of interactions between the tumour and surrounding microenvironment, and interpatient differences, for example. All these factors contribute to the great complexity in the development of a tumour from cancer cells. In the present review, we summarise the knowledge accumulated about the heterogeneity of TCs. Further research in this direction should help to gain a better understanding of the underlying mechanisms contributing to the development and diversity of TCs, paving the way toward more effective treatment strategies.

NONINVASIVE ENCAPSULATED ANAPLASTIC THYROID CARCINOMA PROMISING AN EXCELLENT CLINICAL COURSE: A CASE REPORT AND REVIEW OF THE LITERATURE

Context

Noninvasive encapsulated anaplastic thyroid carcinomas (NE-ATCs) have been described in few case reports, and consistently associated with favorable outcome compared to the classical ATCs.

Objective

Our aim is to remark a rare histological finding in ATCs, encapsulation, which has been associated with a favorable outcome.

Design

We have documented a rare case of an NE-ATC with its clinical, pathological, and molecular features. We also provided a thorough discussion of all the encapsulated ATCs reported in the literature.

Subjects and Methods

A 50-year-old woman with an unremarkable medical history, who presented with a thyroid nodule, and diagnosed as "follicular lesion of undetermined significance" by fine needle aspiration biopsy. The patient was lost to follow-up for six years and revisited upon her neck disturbances and underwent total thyroidectomy.

Results

Sections of the right lobe revealed a grossly encapsulated nodular lesion, measuring 75x55x55 mm. Histologically, the tumor consisted of both carcinomatous and sarcomatous components supported by immunohistochemical stains. Necrosis and atypical mitotic figures were evident. Capsular and/or vascular invasion was not identified. There were no BRAF codon 600, KRAS, NRAS mutations and RET/PTC rearrangement. During three-month follow-up, the patient was free of disease without adjuvant therapy.

Conclusion

Encapsulated ATCs tend to follow a favorable clinical course and may deserve conservative treatment approaches.

The role of surgery in anaplastic thyroid cancer: A systematic review

OBJECTIVE

To elucidate the role of surgery in the management of anaplastic thyroid cancer.

METHODS

Ovid MEDLINE, Cochrane Library, and Google Scholar databases were searched for publications from December 2000 to July 2016. Selection criterion was a focus on the management of anaplastic thyroid cancer in adults. Studies addressing only nonsurgical management and review articles were excluded. Data extraction was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Kaplan-Meier analysis was performed on a subset of patients.

RESULTS

40 publications were included in the study. Approaches to unresectability and interpretations of resection varied widely. For patients undergoing primary surgery, the median survival was 6.6months. The median survival for non-surgical patients was 2.1months. In the subgroup analysis, the median survival time for patients undergoing surgery was significantly longer in Stage IVB (p=0.022) but not IVC disease. Negative margins did not afford a statistically significant survival benefit.

CONCLUSION

Surgery is a mainstay of treatment for Stage IVA and IVB disease. For Stage IVC cancer, distant metastasis was not a strict criterion against surgical candidacy among surgeons. The extent of resection and the definition of resectability remain controversial. Negative margins did not significantly increase survival.