The role of thyroid FNA cytology in pediatric malignant lesions: An overview of the literature

Malignant risk of pediatric Bethesda category III thyroid nodules subcategorized by nuclear atypia and other: A single institution experience

BACKGROUND

The 2023 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) divides AUS diagnoses into two major subcategories: atypia of undetermined significance (AUS) nuclear atypia (AUS-N) and other (AUS-O). This study aims to compare the histological outcome and malignant rate of pediatric AUS thyroid nodules classified into AUS-N and AUS-O subcategories.

DESIGN

A search of our institutional electronic pathology database for the period from January 2012 to July 2023 was conducted to identify pediatric (<21 years old) thyroid nodules that were interpreted as AUS and subsequently had surgery. Cases were further divided into AUS-N and AUS-O subcategories. Results of follow-up surgical resections were collected. The malignant rate was calculated and compared between AUS-N and AUS-O groups.

RESULTS

The study identified 62 thyroid nodules from 58 pediatric patients. Among these nodules, 29 and 33 were subcategorized as AUS-N and AUS-O, respectively. Both groups exhibited a female predominance and displayed a similar nodule size distribution. Histological analysis revealed 15 carcinomas in AUS-N nodules, including 11 cases of classic papillary thyroid carcinoma (PTC) and four cases of follicular type of PTC. In contrast, in the AUS-O group, a total of five carcinomas were documented, including two PTCs and three oncocytic thyroid carcinomas. Notably, the malignant rate of AUS-N nodules (52%) is significantly higher than that of AUS-O nodules (15%) (p = .002).

CONCLUSION

In pediatric AUS thyroid nodules, the malignant risk in AUS-N is significantly higher than that in AUS-O. These findings may guide more appropriate clinical triage and/or improve management of pediatric patients with AUS thyroid nodules.

Diagnostic Value of Preparing Additional Liquid-Based Cytology Slides and Cell Blocks from Residue Material in Thyroid fine Needle Aspiration

Background and Aims

After liquid-based cytology (LBC) technique developed for cervical cytology, it has been used for nongynecological samples and has been very successful. It offers having extra slides of the samples for further examination and ancillary tests. Moreover, cell blocks can be formed from the residue material. The study aimed to evaluate the importance of preparing a second LBC slide or a cell block from the residue material of thyroid fine needle aspiration (FNA) samples to reach a definitive diagnosis in cases diagnosed as nondiagnostic (ND) after the first slide.

Material and Methods

Seventy five cases diagnosed as ND after the first slide were included in study. For 50 cases, the second LBC slides were prepared (LBC group); for 25 cases, cell block was performed from residue material (CB group). Two groups were compared in terms of reaching a definitive diagnosis.

Results

At the end of secondary procedures, a definitive diagnosis was reached in a total of 24 cases (32%). Twenty of 50 cases (40%) in LBC group reached a definitive diagnosis while four cases (16%) in the CB group reached a definitive diagnosis. Achieving a definitive diagnosis was found statistically higher in the LBC group in which the second slide was formed compared to the CB group (P =0.036).

Conclusion

Preparing a second slide with LBC method is more purposive than preparing a cell block from the residue material of thyroid FNA samples. Reducing the percentage of ND cases will protect patients from complications and morbidity that may arise from repeated FNA.

Cytological evaluation of thyroid nodules in children and young adults: a multi-institutional experience

PURPOSE

The utility of the Bethesda system for reporting thyroid cytopathology is debatable in determining the risk of malignancy in pediatric patients. Moreover, the upper age limit for defining the pediatric group has varied across different studies. The aim of this study is to compare the risk of malignancy (ROM) and risk of neoplasia (RON) across different Bethesda categories between the pediatric, young adult, and adult patients.

METHODS

This is a retrospective multi-institutional study performed in three Indian hospitals. ROM was calculated and compared across Bethesda categories in adult (>18 years) and pediatric age groups (≤18 years), with a subgroup analysis in young adults (19-21 years).

RESULTS

Thyroid nodules from a total of 5958 patients were subjected to fine needle aspiration. Of these 199 were pediatric (3.3%) and follow-up histology was available in 2276. The ROM and RON rates, including overall ROM/RON, were significantly higher in pediatric age group as compared to adults. Overall ROM of suspicious for malignancy and malignant categories was higher in children as compared to adults. The overall surgical resection rates were also higher in pediatric patients (45.2% vs. 35.7%; p < 0.01). The similar trend of increased ROM, RON and resection rates was seen among young adults as compared to adult age group.

CONCLUSION

Thyroid nodules presenting in children are more likely to be malignant than those in adults. Importantly, the young adult group behaved in a similar manner with regard to surgical resection rates, ROM and RON to pediatric.

Treating papillary and follicular thyroid cancer in children and young people: Single UK-center experience between 2003 and 2018

AIM

Differentiated thyroid cancer (DTC) in children and adolescents is rare and data about its presentation and management are not well known. The aim of this study was to provide evidence of the current practice in the United Kingdom before the launch of the Rare National Paediatric Endocrine Tumours Guidelines (to be published in 2020).

METHODS

Seventy-two children and adolescents with DTC (<18 years) who were treated at our institution between 2003 and 2018 were identified and their presentation, treatment and outcomes were reviewed.

RESULTS

Median age at presentation was 12.7 years [range: 1-18] and fifty-two (72%) were girls. Fifty (69.4%) children and adolescents presented with a thyroid nodule. Thirteen (18%) had cervical adenopathy and seven of them (54%) underwent an excision biopsy under GA. Eight patients (11%) had evidence of lung metastases at presentation. Twenty-four patients (33%) underwent a hemithyroidectomy and 22 of those had a completion thyroidectomy subsequently, ten (14%) a total thyroidectomy alone and 37 (51%) a total thyroidectomy with lymph nodes dissection. Seventy patients (97%) underwent adjuvant RAI at our institution. The median number of children and adolescents managed per year was five [range: 0-10]. After an overall median follow-up of 40 months, eight patients (11%) had developed recurrent disease. The 1- and 5-year recurrence-free-survival-rates were 93% and 87%, respectively. Overall survival was 100%, with eight children and adolescents (11%) being alive with disease.

CONCLUSION

This study confirms that DTC in children and adolescents is uncommon, is frequently advanced at presentation and has considerable recurrence rates. Despite this, overall survival is excellent. Although the work-up was generally appropriate (image-guided cytology), open biopsy for the diagnosis of lymph node involvement was still employed. The introduction of a specific UK guideline for this age-group will likely result in more tailored-made treatment-pathways and thereby hopefully improve quality and outcomes even further.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

Level IV.

Thyroid surgery in children and young adults: potential overtreatment and complications

Purpose

Thyroid nodules in the pediatric population are more frequently associated with malignant thyroid disease than in adult cohorts. Yet, there is a potential risk of surgical overtreatment. With this single center study, an analysis of potential overtreatment for suspected malignant thyroid disease in children and young adults was aimed for.

Methods

In a period from 2005 to 2018, 155 thyroid operations in children and young adults performed at the University Medical Center Mainz, Germany, were analyzed (patient age 3–20 years, 117 female). Cases were categorized for preoperative diagnosis: non-malignant (group I, n = 45) and malignant thyroid disease (group II, n = 110). Postoperative parameters (histology, complication rates) were assessed and compared between groups.

Results

91.1% of group I were histologically benign. 44.5% of group II harbored malignancy. Permanent hypoparathyroidism was documented in group I (2.7%) and in group II (1.4%, p = 1.000). Wound infections were absent in group I but observed in group II (0.9%, p = 1.000). Transient vocal cord palsy was recorded only in group I (2.3%, 2/85 vs. 0/177 nerves at risk, p = 0.104). Permanent vocal cord palsies were absent.

Conclusion

Preoperative diagnoses were correct in over 90% of group I and in nearly 45% of group II. The high proportion of carcinomas in group II ruled out the issue of potential overtreatment. The risk of severe postoperative complications was equally low in both patient groups.

Electronic supplementary material

The online version of this article (10.1007/s00423-020-01896-x) contains supplementary material, which is available to authorized users.

Bethesda System for Reporting Thyroid Cytopathology in Pediatric Thyroid Nodules: Experience of a Tertiary Care Referral Center

Context.—

The Management Guidelines for Children with Thyroid Nodules and Differentiated Thyroid Cancer from The American Thyroid Association recommends fine-needle aspiration (FNA) as an essential tool for evaluation and management of pediatric thyroid nodules, and The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) as a guideline to categorize FNA cytologic findings. A few publications have focused on TBSRTC categorization in children.

Objective.—

To evaluate our institutional experience of using TBSRTC in the pediatric population.

Design.—

We conducted a retrospective data search for thyroid FNA specimens from patients younger than 21 years who were assessed by using TBSRTC categorization between January 1, 2011, and September 30, 2017. Cytologic and histologic diagnoses, rate of surgical follow-up, rate of histology-proven malignancy, and cytologic-histologic concordance were assessed in comparison with our previously published adult experience.

Results.—

Among a total of 201 specimens, benign category accounted for 103 (51.2%), followed by 35 (17.4%) malignant, 30 (14.9%) atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS), 14 (7.0%) nondiagnostic, 10 (5.0%) follicular neoplasm/suspicious for follicular neoplasm (FN/SFN), and 9 (4.5%) suspicious for malignancy (SFM) categories. Surgeries were subsequently performed in 100 of the 201 cases (49.8%). All surgically removed nodules categorized as malignant and SFM by FNA showed malignancy, while malignancy was evident in various proportions of specimens classified as AUS/FLUS (5 of 16; 31.3%), FN/SFN (1 of 9; 11.1%), and nondiagnostic (1 of 7; 14.2%). No malignancy was identified in the benign category. Cytologic-histologic concordance achieved 100% in malignant, SFM, and FN/SFN categories, and exceeded beyond 85% and 50% for benign and AUS/FLUS categories, respectively.

Conclusions.—

TBSRTC is effective for appropriate categorization of pediatric thyroid nodules. Risk of malignancy in thyroid nodules is higher for the pediatric than adult population. Understanding the difference in TBSRTC categorization between children and adults may aid in achieving more appropriate evaluation and management of pediatric thyroid nodules.

Malignant risk of indeterminate pediatric thyroid nodules-An institutional experience

BACKGROUND

Few studies focus on pediatric thyroid nodules categorized under indeterminate diagnostic categories. The current study was conducted to assess the risk of malignancy of indeterminate pediatric thyroid nodules.

METHODS

A search of the institutional electronic pathology database from 01/2011 to 09/2018 was performed to identify pediatric (<21 years old) thyroid nodules that were interpreted as follicular lesion of undetermined significance (FLUS), suspicious for follicular neoplasm (SFN), or suspicious for malignancy (SFM) and subsequently managed with surgery, repeat fine-needle aspiration (FNA), or ≥ 6 months of clinical/imaging monitoring. Results of follow-up (F/U) surgical resections and repeat FNA/Afirma tests, and clinical and radiologic data were collected.

RESULTS

We identified 46 cases from 42 patients (11-20 years old, 33 females and 9 males), including 30 FLUS, 10 SFN, and 6 SFM. Twenty-five FLUS, ten SFN, and six SFM cases underwent surgery. The histology revealed carcinomas in 36% of FLUS, 20% of SFN, and 100% of SFM categories; follicular adenomas in 32% of FLUS and 80% of SFN categories; and benign nodules in 32% of FLUS category. All five nonsurgically treated FLUS cases were considered benign based on the findings of repeat FNA/Afirma tests (n = 3, 3-22 months F/U) or clinical/radiologic exams (n = 2, 8-12 months F/U).

CONCLUSIONS

Based on a limited study cohort, malignancy was identified in 36%, 20%, and 100% of surgically managed pediatric thyroid nodules categorized as FLUS, SFN, and SFM, respectively; suggesting a markedly higher malignant rate than the implied malignant risk for FLUS and SFM categories in adults.

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.