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A Dissertation submitted to the Faculty of Health Sciences of University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Medicine in Surgery. Johannesburg, 2017 / Background: Hurthle cell neoplasms (HCN) are considered a variant of follicular thyroid neoplasms, and accounts for 3-10% of neoplasms of the thyroid gland. They include Hurthle cell adenomas (HCA) and carcinomas (HCC). Differentiating HCA from HCC preoperatively is currently not possible. We retrospectively searched for demographic and histopathological factors which can be used to predict the risk of malignancy in HCN. Aim: To determine the prevalence of HCC and its demographic factors and histopathological features that can be used to predict the risk of malignancy in HCN. Methods: Records of all patients who underwent thyroidectomy at Academic Hospitals associated with University of the Witwatersrand from January 2001 to October 2015 were reviewed. Patients’ demographic data and the final histology of HCN were further analyzed including pre-operative fine needle aspiration cytology (FNAC) results. Data collected included patients’ demographic, final histology, tumor size and preoperative FNAC result. Data was entered into Excel Spreadsheet and analyzed using STATICA 13.1 program. Results: At total of 2641 records of thyroidectomies were found of which 25.6% (676/2641) were for thyroid neoplasms. Only 15.8% (107/676) of the neoplasms were HCNs and 25.2% (27/107) of HCNs were HCCs. Hurthle cell carcinoma made up 5.6% (27/481) of thyroid carcinomas. 70.4% (19/27) of HCCs were incidentally found following thyroidectomy for multinodular goiter (MNG). The mean tumor size was significantly greater for carcinomas than for adenomas (4.9 cm vs. 3.5 cm; p = 0.016). The risk of malignancy increased from 11.1% when the size was less or equal to 1cm, through 33.3% for size of 1-4cm to 51.8% when the size was greater than 4cm in diameter. A total of 58 FNACs results of 107 HCNs were available for further analysis. Thirty one (53.4%: 31/58) of FNAC results were suspicious for HCN (Bethesda IV), seven (12.1%: 7/58) suspicious of papillary carcinoma (Bethesda V) and eight (13.8%: 8/58) were reported as benign (Bethesda II). Around 10.3% (6/58) were non-diagnostic (Bethesda I) whereas 8.6% (5/58) were reported as atypia of unknown significance (Bethesda III). Both HCA and HCC were more prevalent in females, 88.7% (71/80) and 77.8% (21/27); respectively. The mean age of the patients who had HCA and HCC in years was 52.3+/- 15.6 SD and 55.0 +/- 15.0 SD, respectively. Conclusion: Majority of HCCs are diagnosed following thyroidectomy for benign disease. Close to a quarter of HCNs are malignant and the risk of malignancy increases with size. Age and gender are not useful to predict malignancy in HCNs. We recommend total thyroidectomy for thyroid nodule greater than 4cm in diameter if FNAC result is suggestive of HCN as the risk of malignancy is above 50%. / MT2017

A cytochemical analysis was undertaken of C cells of thyroid glands obtained from sixteen young oogs and five human s t ill - b o r n neonates. Tissues were fixed in selective liquid fixatives (N e lly 's , Carnoy s, glutaraldehyde-picric-acetic acid, glutaraldehyde-potassium dichromatesodium sulphate and formol-saline) or fixed in formalin vapour a f t e r freeze drying. Cryostat sections and some of the above fixatives were used for enzyme demonstration. Simple and conjugated proteins in the cytoplasm of canine C cells were studied by numerous cytochemical reactions. Acetylatiun, methylation, benzoylation, nitrosation, acid hydrolysis and aldehyde blockade as well as enzyme hydrolysis were employed to evaluate the aldehyde fuchsin, colloidal iron, toluidine blue and periodic acid-Schiff staining reactions in canine C cells. I have confirmed that the cytoplasm of canine C cells contains an abundance of acidic protein groups which are due to side-chain carboxyls. Mild acid hydrolysis, amongst other reactions, may result in peptide hydrolysis at the aspartyl group, which hydrolysis contributes to the anionic charge in the C cell cytoplasm. Basic proteins are not readily stained in the canine C c e l l . Bisulphide groups are numerous and their oxidation adds to the negative charge of the C cell cytoplasm. I found that the positive aldehyde fuchsin and colloidal iron reactions are not attributa ole to mucosubstances such as sulphomucms, sialomucins or acidic mucopolysaccharides, but seem to be imparted by an acidic protein unconjugated to polysaccharide. A positive aldehyde fuchsin reaction probably depends on both disulphidc and carboxyl groups within C c e lls . A positive colloidal iron reaction in canine C cells requires the presence of carboxyl groups but an increased number of these groups does not enhance the staining reaction. The conditions required generally for s ilv e r binding and more specifically for the Grimelius s ilv e r impregnation in canine C cells were evaluated by oxidation and various other cytochemical procecures. I found that the argyrophilia of thyroid C colls depends upon an exogenous reducing agent and upon pH, optimal impregnation occurring at a s lig h tly acid pH. Oxidation preceding s ilv e r impregnation by the Grimelius method, reduces the a f f i n i t y of structures in the cell for s ilv e r n itr a te . Indirect evidence supports the view that argyrophilia in the C cells depends upon disulphide groups. I t is suggested that s ilv e r nitrate and disulphide groups react in C cells to form silv e r nercaptide which produces the argyrophilia. The presence of C cel s was demonstrated in human neonates by means of cytochemical methods known to demonstrate C cells in dogs. C cells were found predominantly in the posterior region and upper pole of both lobes where they were found scattered in clusters of six to eight cells per high power f i e l d Two morphological forms of normal human C cells were observed - an ovoid cell and one with cytoplasmic processes. By demonstrating oxidative enzymes and masked metachromasia, three categories of e p ith e lia l cells have been shown in the neonatal thyroid gland : A ( f o l l i c u i a r ) , C and AC (intermediate) c e lls . The l a t t e r may be homologous with the oxyphil cells observed in normal and pathological adult thyroid glands. The c lin ic a l applications in which I have useo the results of the above studies are outlined in the la s t section of the dissertation.

by Poon Yim-chu Daisy. / Bibliography: leaves 128-148 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983

by Lam Kang Yau. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 127-143). / Acknowledgements --- p.iii / Abstract --- p.iv / List of abbreviations --- p.vi / Introduction --- p.1 / Literature review / Chapter A. --- Historical background --- p.6 / Chapter B. --- Histology on the epidermis of squamate reptile --- p.8 / Chapter C. --- The effects of thyroid hormone on the integument in the vertebrate --- p.13 / Chapter D. --- Extrathyroidal conversion of T4 to T3 --- p.18 / Experiment 1. The study of epidermal cellular changes and the effect of Tx on the sloughing cycle of Elaphe taeniura / Introduction --- p.21 / Materials and methods --- p.22 / Results --- p.26 / Discussion --- p.34 / Experiment 2. To study the extrathyroidal conversion of T4 to T3 (5'-D activities) of Elaphe taeniura / Introduction --- p.47 / Materials and methods --- p.48 / Results --- p.52 / Discussion --- p.54 / Experiment 3. The study of the effects of T3 and Tx on the sloughing cycle of Elaphe taeniura and in vitro 5'-deiodinating activities / Introduction --- p.56 / Materials and methods --- p.58 / Resul ts --- p.63 / Discussion --- p.81 / Experiment 4. The study of plasma T3 and T4 levels during the sloughing cycle of Elaphe taeniura / Introduction --- p.111 / Materials and methods --- p.112 / Results --- p.114 / Discussion --- p.115 / General discussion --- p.120 / Summary and conclusions --- p.125 / References --- p.127

Thesis (M.Sc.)--Chinese University of Hong Kong, 1975. / Bibliography: l. 157-179.