Abstract
Introduction
Display of Data
Materials and Methods
Results
Discussion
Conclusion
Abstract
The aim of this project was to investigate the incidence of follicular carcinoma in follicular lesions as reported by fine needle aspiration (FNA) in King Abdulaziz University Hospital. It was observed that a high percentage of these follicular lesions were benign. Of major concern is that a large percentage of these clients undergo surgery to establish a diagnosis. It is advocated that alternative measures should be adopted to reduce unnecessary surgeries. Hence, reducing cost, morbidity and the psychological impact on the patient of uncertain diagnosis through alternative measures could be beneficial.
Introduction
Thyroid follicle is located in the thyroid gland. It is surrounded by cubical epithelial cells. Within the follicular lumen is colloid tissue and separating one follicle from another are red blood cells. Cubical epithelial cells contain thyrotrophic receptors, which respond to thyroid- stimulating hormones. Follicular cells have embryologic origin of the foramen cecum (Walter, 2003).
Function
Cubical epithelial cells absorb iodine and amino acids from surrounding red blood cells. Thyroglobulin and thyroperoxidase are synthesized from amino acids, which along with iodine are secreted in the thyroid follicular cells. Subsequently, through endocytosis epithelial cells utilize iodinated thyroglobulin to produce thyroid hormones. These are then diffused into the blood stream (Walter, 2003).
Thyroid Follicular Lesions
Thyroid follicular lesions can be placed into four main categories, follicular carcinoma, follicular adenomas; multinodular goiter (MNG) and Hashimotos Thyroiditis. The focus of this research is to prove that many surgeries could be avoided if only there were distinct methods differentiating these lesions through efficient diagnostic testing. Differentiating between adenomas and carcinoma lesions has caused great difficulty and has been topic of much research in the past.
Materials and Methods
A retrospective data was collected from patient's records that had thyroidectomy either total or partial with a preoperative FNA finding of follicular lesions. The data collected also included sex, age, ultrasound finding and final histopathology report on the surgical specimen. In total 46 patients were observed from June 2010 – Dec 2012. 39 were females and 7 males.
Results
Summary of histopathology of follicular lesions found by FNA
Out of the 46 patients that were reviewed 1(2.2%) was found to be follicular carcinoma(Ca), while 6(13%) were papillary carcinoma of follicular variant,4 (8.6%) papillary ca,1(2.2%) medullary and 3(6.5%) Hurthel. The total malignant conditions hence accounted for 32.5%. MNG was represented by 15 (32%) of cases, Hshimotos thyroiditis 8(17%), follicular adenoma 6(13%) and nodular hyperplasia 2(4.4%). Hence, the total benign conditions represented 68%, suggesting that the majority of cases reported as follicular lesion by FNA are found to be benign when follicular carcinoma as a separate entity was only represented by 2.2%.
Tabulated Data
*** Sample was done outside of the institution
** Solitary Thyroid Nodules
* Multinodular Goiter
Discussion
Fine needle Aspiration
Fine-needle aspiration is a minor surgical intervention, which is less painful than other surgical biopsies and less costly. The main reason for conducting a fine needle aspiration is to diagnose suspicious cases as well as decide on treatment management. Research has shown the value of fine-needle aspiration (FNA) in reaching a diagnosis, hence, avoiding unnecessary surgery (Komen, 2012).
This has not been found to be the case when dealing with follicular lesions due the difficulty in differentiating between follicular carcinoma and adenoma on the basis of cystomorphology (Deveci, et. al 2006). There is also the added problem with numerous benign conditions such as MNG and Hashimotos thyroiditis that can be represented by follicular lesions on FNA.
Supportive Research Findings
Studies conducted by Jo (2010) and counterparts supported the assumption that a major portion of fine needle aspirations conducted on patients with thyroid lesions result in discovery of benign tumors. These researchers reviewed 3,080 fine needle aspiration samples. The standardized 6 tier nomenclature cytology and histology follow up was applied. It was revealed that 18.6% were non-diagnostic and 59.0% benign (Jo et.al, 2010).
Further, a 3.4% were atypical follicular lesion of undetermined significance (AFLUS), 9.7% were suspected for follicular neoplasm (SFN), in 2.3% there were suspicions for malignancy (SM), and 7.0% were malignant. The follow up proved that of 574 cases originally perceived as non-diagnostic, 47.9% maintained that status (Jo et.al, 2010).
In 892 cases, there was follow-up histology in 892 revealed non-diagnostic, 8.9%; benign, 1.1%; AFLUS, 17% (9/53); SFN, 25.4%; SM, 70% (39/56), and malignant, 98.1%.
They concluded that this new standardized nomenclature could enhance inter-laboratory correlations, which can eventually become more reliable in differentiating between benign and malignant thyroid follicle lesions (Jo et.al, 2010).
Xing (2011) and colleagues conducted research to establish criteria for differentiating between benign and malignant thyroid follicular lesions during diagnostic testing. The researchers utilized elastography to test the efficacy of sonography diagnostic evaluation of thyroid follicular lesions. Strain ratio calculations were further applied (Xing et.al, 2011).
They concluded that strain ratio measurement of thyroid lesions is a very useful standardized method for analyzing stiffness inside the areas that were examined. Consequently, it was recommended as an additional tool, which can be incorporated with B-mode sonography in enabling diagnostic performance (Xing et.al, 2011). Researchers further advanced that overlapping cytology features can create misdiagnoses when using FNA only (Deveci, et. al 2006). This has been the case in my study where a multitude of conditions were represented by the FNA finding of follicular lesion with 68% being benign.
Conclusion
This research set out to prove that most surgery carried out for follicular lesions is unnecessary as the majority of the conditions were benign. Although FNA can be accurate in the diagnosis of many conditions, it falls short when reaching a diagnosis in Thyroid follicular lesions and as was shown follicular carcinoma only represented 2.2% of the total cases. Hence, there is the need for some other form of confirmative diagnostic procedure. Suggestions can include the strain ratio measurement of thyroid lesions combining B-mode sonography (Xing,et al,2011) and universal application of a new standardized nomenclature (Jo,et al 2010).
References
Deveci, M. Deveci, G. LiVolsi, V., & Zubair, B ( 2006). Fine-needle aspiration of
follicular lesions of the thyroid. Diagnosis and follow-Up. Cytology, 3(9)
Jo,Y. Stelow, E. Dustin, M..& Hanley, Z. ( 2010). Malignancy risk for fine-needle aspiration of
thyroid lesions according to the Bethesda System for Reporting Thyroid Cytopathology.
Komen, S (2012). Fine Needle Aspiration. The Cure
Walter, F. (2003). Medical Physiology: A Cellular and Molecular Approach.
Elsevier/Saunders.
Xing, P. Wu, L. Zhang, C. Li, S. Liu, C., & Wu C. (2011). Differentiation of benign from
malignant thyroid lesions: calculation of the strain ratio on thyroid sonoelastography. J
Ultrasound Med, 30(5):663-9.
Medicine: Thyroid carcinoma in follicular lesions
