Anaplastic thyroid carcinoma: cytomorphology and clinical implications of fine-needle aspiration

2021 American Thyroid Association Guidelines for Management of Patients with Anaplastic Thyroid Cancer

Background: Anaplastic thyroid cancer (ATC) is a rare but highly lethal form of thyroid cancer. Since the guidelines for the management of ATC by the American Thyroid Association were first published in 2012, significant clinical and scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, and researchers on published evidence relating to the diagnosis and management of ATC. Methods: The specific clinical questions and topics addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of the Task Force members (authors of the guideline). Relevant literature was reviewed, including serial PubMed searches supplemented with additional articles. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations. Results: The guidelines include the diagnosis, initial evaluation, establishment of treatment goals, approaches to locoregional disease (surgery, radiotherapy, targeted/systemic therapy, supportive care during active therapy), approaches to advanced/metastatic disease, palliative care options, surveillance and long-term monitoring, and ethical issues, including end of life. The guidelines include 31 recommendations and 16 good practice statements. Conclusions: We have developed evidence-based recommendations to inform clinical decision-making in the management of ATC. While all care must be individualized, such recommendations provide, in our opinion, optimal care paradigms for patients with ATC.

Pitfalls in Thyroid Cytopathology

Fine-needle aspiration (FNA) is among the first diagnostic tools used in the evaluation of thyroid nodules. It has the ability to triage patients with benign and malignant lesions, thus defining the optimum clinical and/or surgical management. The Bethesda System for Reporting Thyroid Cytopathology has found worldwide acceptance. Thyroid FNA offers high positive predictive value (97%-99%), with sensitivities and specificities of 65% to 99% and 72% to 100%, respectively. Nonetheless, many potential diagnostic pitfalls exist that can lead to false-positive and/or false-negative results. This article discusses several of the potential pitfalls in the cytologic evaluation of thyroid lesions.

Cytologic features of aggressive variants of follicular-derived thyroid carcinoma

Certain carcinomas of the thyroid gland behave aggressively resulting in increased patient morbidity and poor patient prognosis. The diagnosis of these aggressive thyroid cancer subtypes is sometimes challenging and subject to increased interobserver variability. This review deals with the cytological features of such tumors including aggressive variants of papillary thyroid carcinoma, poorly differentiated thyroid carcinoma, and anaplastic thyroid carcinoma. These malignancies fall into 2 groups based on their cytomorphology: those that exhibit distinct microscopic features (eg, nuclear findings typical of classical papillary thyroid carcinoma or marked anaplasia) and those that present with more subtle cytologic features (eg, nuclear pseudostratification, "soap bubble" nuclei, supranuclear or subnuclear cytoplasmic vacuoles, rosette-like structures, hobnail cells). We review the literature regarding these aggressive thyroid cancers and highlight important phenotypic characteristics that can be useful for their diagnosis based on fine needle aspiration.

Aggressive variants of follicular cell-derived thyroid carcinomas: a cytopathologist's perspective

Follicular cell-derived carcinomas of the thyroid gland comprise a heterogeneous group of malignant neoplasms of the thyroid gland with varied histologic appearance and molecular profiles. In most patients, these tumors represent relatively indolent neoplasms; however, certain subtypes/variants behave in an aggressive manner, and the recognition of this subset of tumors is essential because of their variable response to therapy and significant morbidity and mortality. Fine-needle aspiration is considered an essential tool for the diagnosis of suspicious thyroid nodules. In this review, the authors discuss the clinical, histologic, and molecular findings and the prognostic implications of aggressive thyroid neoplasms with emphasis on the characteristic cytomorphologic features on fine-needle aspiration smears.

American Thyroid Association guidelines for management of patients with anaplastic thyroid cancer

BACKGROUND

Anaplastic thyroid cancer (ATC) is a rare but highly lethal form of thyroid cancer. Rapid evaluation and establishment of treatment goals are imperative for optimum patient management and require a multidisciplinary team approach. Here we present guidelines for the management of ATC. The development of these guidelines was supported by the American Thyroid Association (ATA), which requested the authors, members the ATA Taskforce for ATC, to independently develop guidelines for ATC.

METHODS

Relevant literature was reviewed, including serial PubMed searches supplemented with additional articles. The quality and strength of recommendations were adapted from the Clinical Guidelines Committee of the American College of Physicians, which in turn was developed by the Grading of Recommendations Assessment, Development and Evaluation workshop.

RESULTS

The guidelines include the diagnosis, initial evaluation, establishment of treatment goals, approaches to locoregional disease (surgery, radiotherapy, systemic therapy, supportive care during active therapy), approaches to advanced/metastatic disease, palliative care options, surveillance and long-term monitoring, and ethical issues including end of life. The guidelines include 65 recommendations.

CONCLUSIONS

These are the first comprehensive guidelines for ATC and provide recommendations for management of this extremely aggressive malignancy. Patients with stage IVA/IVB resectable disease have the best prognosis, particularly if a multimodal approach (surgery, radiation, systemic therapy) is used, and some stage IVB unresectable patients may respond to aggressive therapy. Patients with stage IVC disease should be considered for a clinical trial or hospice/palliative care, depending upon their preference.

Utilization of ancillary studies in thyroid fine needle aspirates: a synopsis of the National Cancer Institute Thyroid Fine Needle Aspiration State of the Science Conference

The National Cancer Institute (NCI) sponsored the NCI Thyroid Fine Needle Aspiration (FNA) State of the Science Conference on October 22-23, 2007 in Bethesda, MD. The 2-day meeting was accompanied by a permanent informational website and several on-line discussion periods between May 1 and December 15, 2007 (http://thyroidfna.cancer.gov). This document summarizes matters regarding the utilization of ancillary studies in thyroid FNA (http://thyroidfna.cancer.gov/pages/info/agenda/).

Diagnosis of malignant epithelial thyroid lesions: fine needle aspiration and histopathologic correlation

Fine needle aspiration is a diagnostic tool useful as a guide to patient management. We believe that its role in solving the diagnostic dilemmas presented by thyroid nodules is still underappreciated. Current fiscal constraints in health care might bring about a wider use of this simple technique to select patients for surgery. Care in sampling a mass is essential to obtain aspirates that are representative of the lesion and adequate in quantity for interpretation. Several aspirates are needed from all but the smallest masses. Most thyroid carcinomas are well-differentiated with a low grade of malignancy. The majority of these are papillary carcinomas, which are easily diagnosed in good cytologic smears. With fine needle aspirates the goal is to diagnose a follicular neoplasm and to separate it from the adenomatoid nodule. The follicular neoplasm then can be classified as adenoma or carcinoma with the histologic sections. The minimally invasive carcinoma still can be challenging to recognize. We hope that the cytologic criteria and histopathologic correlations presented here will help general pathologists who interpret aspirates. We believe that in the near future additional immunohistochemical methods and genetic markers will be used increasingly to discriminate among the neoplasms and to provide prognostic information.

Fine-needle aspiration of anaplastic thyroid carcinoma with varied cytologic and histologic patterns: a case report

Anaplastic carcinoma of the thyroid (ACT) is a rare subtype of thyroid neoplasm. This tumor represents approximately 5-10% of all thyroid malignancies and its poor prognosis has not changed in 25 years. ACT often arises in a long-standing thyroid nodule and has been documented to be associated with a variety of more well-differentiated thyroid carcinomas. We describe the cytologic features of a case in which the patient had a 10-yr history of a thyroid nodule. The ACT in this case had a cytologic and histologic appearance of several different subtypes of thyroid carcinomas.

Simultaneous fine-needle aspiration of thyroid lesions and regional cervical lymph nodes: clinicopathologic implications

Occasionally patients with thyroid nodules to be evaluated by fine-needle aspiration (FNA) biopsy also present with regional cervical lymphadenopathy. Aspiration biopsies should be performed on both the thyroid and nodal lesions. This approach will yield important information about whether the lesions are related, with profound impact on further workup, management, prognosis, and staging.