The number of nucleoli in benign and malignant thyroid lesions: a useful diagnostic sign in cytological preparations

RRS1 gene expression involved in the progression of papillary thyroid carcinoma

Background

Papillary thyroid carcinoma (PTC) is one of the most frequent malignancies of the endocrine system, whose mechanisms of pathogenesis, progression and prognosis are still far from being clearly elucidated. Despite an increasing body of evidences highlights ribosome biogenesis regulator homolog (RRS1) as a ribosome biogenesis protein in yeast and plants, little is known about human RRS1 function.

Methods

Proliferation, cell cycle and apoptosis of PTC cells were assessed following the knockdown of RRS1 expression though MTT, colony formation assay, and flow cytometry. Then, transcriptome profiling was conducted to explore pathway changes after RRS1 silencing in PTC cells. Receiver operating characteristic curve and Youden’s index were performed in twenty-four thyroid carcinoma samples to assess their potential clinical diagnostic value.

Results

Firstly, we found that silencing RRS1 significantly reduced cell proliferation, inhibited cell cycle, and promoted apoptosis in PTC cell line. The result also showed that knock-down of RRS1 could up-regulate genes involving apoptosis and metabolism, while, down-regulate genes relative to cell proliferation and blood vessel development. Notably, the present study confirmed the diagnostic value of RRS1 for thyroid carcinoma in both children and adults.

Conclusions

In conclusion, these data afford a comprehensive view of a novel function of human RRS1 by promoting cell proliferation and could be a potential indicator for papillary thyroid carcinoma.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0519-x) contains supplementary material, which is available to authorized users.

Fine Needle Aspiration Biopsies of the Head and Neck: The Surgical Pathologist's Perspective

Masses of the head and neck comprise a variety of benign and malignant tumors and tumor-like conditions, which may present diagnostic challenges to the surgical pathologist and surgeon. Fine needle aspiration cytology is an increasingly popular technique in the initial evaluation of such lesions. The high diagnostic accuracy of this technique makes it generally preferable to traditional surgical biopsy. It is particularly useful in the sampling of histologically uniform neoplasms of the salivary glands, identification of classical papillary carcinoma and medullary carcinoma of the thyroid, separation of colloid goiter from follicular neoplasms, and confirmation of clinically suspicious lymph node metastases in cases with already documented malignant diseases. Despite its usefulness, aspiration cytology of head and neck lesions has certain inherent pitfalls, and these are briefly examined in this review. Int J Surg Pathol 8(1):17-28, 2000

Well differentiated follicular neoplasms of the thyroid: reproducibility and validity of a 'decision tree' classification based on nucleolar and karyometric features

This study was conducted on fine-needle aspirates of well differentiated follicular neoplasms of the thyroid. A 'decision tree' classification based on the percentage of nucleolated nuclei, percentage of nuclei with two or more nucleoli and mean major nuclear diameter was adopted. We observed that the reproducibility and the validity of the follicular adenoma vs follicular carcinoma discrimination are greater than in the subjective evaluation. Moreover, similar classification results were obtained when measurements were performed either with a fully automated image analysis system or with semiautomatic or manual instrumentation. As for reproducibility of the inter-instrument comparisons, the k statistic values ranged from 0.85 to 1.00 (mean value 0.90, that is, an 'almost perfect' degree of agreement); in the subjective evaluations, the inter-observer comparisons showed values ranging from 0.20 to 0.56 (mean value 0.37, that is, 'fair'). In the decision tree classification, feature value thresholds were selected in order to have specificity of 100% and the predictive value of a positive result (carcinoma) of 100%; accuracy was 87% (range 86-89%), sensitivity 74% (71-79%), the predictive value of a negative result (adenoma) 79% (78-82%). In the subjective evaluation the values were as follows: accuracy 67% (64-71%), sensitivity 57% (50-64%), specificity 77% (71-79%), predictive value of a negative result (adenoma) 64% (61-69%), predictive value of a positive result (carcinoma) 71% (67-75%). The conclusion is that, by using a routine microscope equipped with a micrometer, the preoperative diagnosis of follicular carcinoma from smears can be formulated with a high degree of certainty.

Contribution of fine needle aspiration cytology to diagnosis and management of thyroid disease

AIMS

To determine the role of fine needle aspiration cytology (FNAC) in the diagnosis and management of thyroid disease.

METHODS

Clinical histories of 144 patients who had undergone FNAC of the thyroid were analysed. Clinical presentation, non-invasive investigations including hormone assays, ultrasound, and isotope scan procedures were compared with FNAC diagnoses in all cases and with histological diagnosis in the 28 cases (19%) that had undergone surgery. Clinical management was decided upon combining all of the above investigations. The relative contribution of the FNAC was divided into: essential, additional and non-contributory, misleading.

RESULTS

FNAC diagnoses included: 29 (16%) benign colloid goitre, 56 (39%) benign cystic goitre, 24 (17%) thyroiditis, and 22 (15%) neoplasms. Nineteen (13%) of the specimens were unsatisfactory. When compared with clinical diagnoses based on non-invasive diagnostic investigations FNAC represented no improvement on the diagnosis of benign colloid/cystic goitre (55% v 54% respectively). It represented an improvement on the diagnosis of thyroiditis (9% v 17% respectively). FNAC decreased clinically suspicious lesions in which 22 neoplasms were diagnosed from 37% to 15%. Eleven patients with neoplasms underwent surgery and neoplasms were confirmed histologically. Others including lymphoma, metastatic carcinoma, and analplastic carcinoma were managed conservatively. There were four false negative FNAC diagnoses (3%) in clinically suspicious lesions, found on histology to be benign follicular adenomas.

CONCLUSIONS

FNAC had an essential role in the diagnosis and management of 23% of our patients, a confirmatory role in 61% of patients, a non-contributory role in 13% when specimens were inadequate, and was misleading in 3% where results were false negative. The positive identification of thyroiditis and neoplasia stands on its own as a justification for FNAC.

Quantitative analysis of nucleolar margination in diagnostic cytopathology

The diagnostic value of nucleolar margination, defined as the percentage of nucleoli touching the nuclear membrane, was investigated in 359 cytological preparations of benign and malignant lesions of the thyroid, breast, prostate and central nervous system. Premalignant lesions of the uterine cervix and non-invasive papillary carcinomas of the bladder were also examined. It was observed that the percentages in benign lesions were, in general, lower than in the malignant and that the values increased progressively with increasing grade in the cervix and bladder. When the overlap index was calculated, this gave exact information on the usefulness of nucleolar margination in distinguishing benign from malignant lesions, particularly in the prostate and thyroid and, to a lesser extent, in the breast and central nervous system. As for lesions of different grades, the calculation of the index allowed the identification of two subgroups, one corresponding to low grades (mild cervical dysplasia or urothelial papillary carcinoma of grade 1), the other subgroup to high grades (severe cervical dysplasia and carcinoma in situ, or papillary carcinoma of grade 3). Moderate dysplasia cases and grade 2 papillary carcinomas do not appear as separate intermediate categories but rather show values falling into the range of either the higher or lower grades. The margination values obtained from the cytological preparations corresponded well to those in the histological slides obtained from the resected specimens. In conclusion, nucleolar margination appears to be a feature which is easy to evaluate in a reproducible way and useful in cytological diagnosis.

Value of quantitative nucleolar features in the preoperative cytological diagnosis of follicular neoplasias of the thyroid

Nucleolar prevalence, size, and outline were investigated on cytological material from cold thyroid nodules obtained by fine needle aspiration. The percentage of nucleolated nuclei in follicular adenoma (32 cases) was less than in follicular carcinoma (26 cases). In adenoma most nuclei contained one nucleolus, and nuclei with two or more nucleoli were less common than in carcinoma where most cases showed the highest nucleolar diameter values. There was some overlap between adenomas and carcinomas, however, when the mean of the 10 largest values of the major nucleolar diameter was considered. In follicular carcinoma the percentage of marginated nucleoli--that is, those touching the nuclear membrane--was, in general, greater than 20%; in adenoma the values were equal to or lower than 16%. The overlap index showed that the percentages of marginated nucleoli and nucleolated nuclei are the two best discriminatory features between adenoma and carcinoma.