|Year : 2018 | Volume
| Issue : 1 | Page : 37-42
Histopathological pattern of thyroid diseases in Zaria: A 10-year review
Nasiru Raheem1, Saad A Ahmed2, Modupeola OA Samaila2
1 Department of Histopathology, Federal Medical Centre, Yola, Adamawa State, Nigeria
2 Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, Nigeria
|Date of Web Publication||17-Apr-2018|
Department of Histopathology, Federal Medical Centre, Yola, Adamawa State
Source of Support: None, Conflict of Interest: None
Context: Majority of the previous studies on thyroid diseases in Northern Nigeria focussed mainly on neoplastic lesions. The non-neoplastic lesions are more common and constitute more public health burdens. Aim: To determine the histopathological pattern of thyroid diseases in our region and compare our findings with similar studies in Nigeria and elsewhere. Settings and Design: This is a retrospective study carried out at the Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria, from January 2005 to December 2014 using specified criteria. Subjects and Methods: All cases of thyroid diseases diagnosed histologically within the study period had their histology reports as well as their haematoxylin and eosin-stained slides reviewed and analysed. Statistical Analysis: Statistical package for the social sciences (SPSS) software for windows version 20.0 (IBM SPSS Inc. Chicago, IL) was used. Results: There were 302 thyroid diseases diagnosed during the study period. Only 297 cases fulfilled the study inclusion criteria. There were 255 females and 42 males with a male-to-female ratio 1:6. Ages ranged from 4 months to 80 years, with peak age incidence between 31 and 50 years. Thyroglossal cysts accounted for 17 (5.7%) cases. Non-neoplastic diseases composed of colloid goitre, Graves' disease, Hashimoto thyroiditis and lymphocytic thyroiditis. They accounted for 214 (72.1%), 12 (4.0%), 3 (1.0%) and 1 (0.3%) cases, respectively. The neoplastic diseases comprised 36 (12.1%) adenoma cases and 14 (4.7%) carcinomas, with papillary carcinoma being the most common (71.4%) thyroid cancer. Conclusion: This study showed that thyroid diseases in Zaria had a female predominance with a peak age frequency between 30 and 50 years of age. The most common diseases were colloid goitre, follicular adenoma and papillary carcinoma. These findings are comparable with several studies on thyroid diseases in Nigeria and globally.
Keywords: Histopathology, retrospective, thyroid diseases
|How to cite this article:|
Raheem N, Ahmed SA, Samaila MO. Histopathological pattern of thyroid diseases in Zaria: A 10-year review. Niger Postgrad Med J 2018;25:37-42
|How to cite this URL:|
Raheem N, Ahmed SA, Samaila MO. Histopathological pattern of thyroid diseases in Zaria: A 10-year review. Niger Postgrad Med J [serial online] 2018 [cited 2022 Nov 29];25:37-42. Available from: https://www.npmj.org/text.asp?2018/25/1/37/230193
| Introduction|| |
The incidence of thyroid gland diseases varies with geographical location. In Africa, dietary iodine deficiency is the major determinant of thyroid pathology, resulting in a spectrum of disorders. The principal diseases of the thyroid gland are goitre (diffuse or nodular), hypothyroidism, hyperthyroidism, thyroiditis and neoplasms. Others include congenital anomalies such as thyroglossal cyst, thyroglossal fistula and aberrant thyroid tissue.
Simple (non-toxic) goitre is extremely common throughout the world and is thought to affect >200 million individuals. It is also by far the most commonly observed thyroid disorder in Africa.
Thyroid cancer is a relatively rare malignancy representing only 1.5% of all cancers., It is apparent that the pattern of thyroid disorders in Africa is evolving with increasing iodine sufficiency, despite incomplete biomedical information.
In view of this apparent evolvement of thyroid disorders in Nigeria and Africa at large, this study seeks to document the histopathological pattern of thyroid diseases in our environment and to compare our findings with similar works in Nigeria and globally.
| Subjects and Methods|| |
This study was an analysis of all thyroid specimens submitted to the Pathology Department of Ahmadu Bello University Teaching Hospital, Zaria, over a 10-year period (January 2005 to December 2014). All cases registered as thyroid diseases within the study period were extracted from the departmental records, comprising bench books and histology reports. The patients' request forms filled by the physicians were retrieved for bio-data. All histology slides stained with routine haematoxylin and eosin were retrieved and studied. Fresh sections were made from formalin-fixed, paraffin-embedded stored tissue blocks where slides were missing or broken. They were then examined and reviewed microscopically. Congo red staining for amyloid was carried out to confirm the only case of medullary carcinoma.
The cases were grouped into developmental/congenital, goitre/hyperplastic lesions, inflammatory and autoimmune diseases. The neoplastic lesions were classified using the World Health Organization classification of thyroid tumour.
Cases with missing slides and tissue blocks, all fine needle aspiration specimens as well as post-mortem thyroid samples were excluded from the study.
| Results|| |
A total of 302 thyroid specimens were submitted to the department for histopathological examination during the study period. This constituted 1.1% of the entire surgical specimens. Two hundred and ninety-seven cases fulfilled the inclusion criteria and were analysed. Five cases were excluded due to inability to find both slides and tissue blocks.
There were 255 (85.9%) females and 42 (14.1%) males, with a male-to-female ratio of 1:6. One hundred and ninety-three of the goitre cases were females (90.2%), while 21 (9.8%) cases were males. The male-to-female ratio of goitre cases was 1:9.2. A total of 40 out of the 50 neoplastic cases were females and 10 cases were males, with male-to-female ratio of 1:4. In case of autoimmune/inflammatory diseases, 13 cases were females while three cases were males, giving a male-to-female ratio of 1:4.3 [Table 1].
Thyroid diseases affected individuals from all age groups ranging from 4 months to 80 years, with peak age incidence between 31 and 50 years [Table 2]. More than one-half, i.e., 167 (56.2%), of the total cases encountered in this study occurred within this age range (31–50 years). Goitre was the only thyroid disorder found in all the age groups, while thyroglossal cysts were predominantly found within age bracket of 0–10 years [Table 2]. The ages of eight cases were not specified from the accompanied request forms. Of these, four were goitres, three benign neoplasms and a case of Graves' disease [Table 2].
The most common thyroid disease in this study was colloid goitre which accounted for 214 cases (72.1%), followed by neoplastic diseases that constituted 50 (16.8%) of the total cases. Seventeen cases (5.7%) were thyroglossal cysts while 16 (5.4%) cases were autoimmune/inflammatory disorders.
Majority (64.7%) of the 17 cases of the thyroglossal cysts were seen in children aged 4 months to 10 years, with slight female preponderance [Table 2].
There were 12 autoimmune/inflammatory disorders which included eight cases of Graves' disease, three cases of Hashimoto thyroiditis and a case of lymphocytic thyroiditis. The peak age of occurrence is 21–30 years with a male-to-female ratio of 1:4.3. All the three cases of Hashimoto thyroiditis were exclusively seen in females. Both Graves' and Hashimoto thyroiditis seen in this study showed variable degree of lymphocytic infiltrates as well as lymphoid follicles [Figure 1]. The major difference was the follicular architecture and cytomorphology of the lining cells. In the case of Hashimoto thyroiditis, the follicles were atrophic with cuboidal cells lining, whereas in the cases with Graves' disease, the follicles were hyperplastic with columnar cells lining.
|Figure 1: Photomicrograph of Graves' disease showing hyperplastic follicles with papillary infoldings and area of lymphoid aggregates. (H and E, ×100)|
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A total of 65.4% of the goitre cases occurred in the age groups 31–50 years [Table 2]. One hundred and ninety cases (88.8%) of goitre were nodular colloid goitre, while multinodular goitre accounted for the remaining 24 cases (11.2%).
Neoplastic disorders were the second most common and accounted for 50 (16.8%) of all the cases studied. The benign neoplasms (adenoma) were 36 cases (72%) while the malignant cases constituted the remaining 14 (28%). Thirty-three (91.6%) of these benign neoplasms were follicular adenoma, two cases (5.6%) were Hürthle cell adenoma which microscopically showed round cells with vesicular nuclei, prominent nucleoli and eosinophilic granular cytoplasm arranged in trabeculae pattern and a solitary case (2.8%) of trabecular adenoma that showed cells arranged in trabecular pattern containing both intracellular and extracellular hyaline materials [Figure 2] and [Table 3]. The peak age of occurrence of these benign neoplasms was 31–40 years, with a male-to-female ratio of 1:5 [Table 1].
|Figure 2: Photomicrograph of trabecular adenoma showing elongated cells in trabecular pattern with both intra- and extra-cellular hyaline materials. (H and E, ×100)|
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Malignant neoplasms accounted for 4.7% of the total cases in this study. The peak age of occurrence is between 21 and 30 years, with male-to-female ratio of 1:2.5. Ten (71.4%) out of the 14 thyroid cancer cases were papillary carcinoma, two cases (14.3%) were follicular carcinoma and a case each (7.1%) of medullary and undifferentiated carcinoma [Table 4]. [Figure 3] and [Figure 4] showed photomicrographs depicting the histology of colloid goitre and thyroglossal cyst lined by respiratory type epithelium with goblet cells.
|Figure 3: Photomicrograph of a colloid goitre showing thyroid follicles of varying sizes containing colloid. (H and E, ×200)|
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|Figure 4: Photomicrograph showing thyroglossal cyst lined by respiratory type epithelium with goblet cells. (H and E, ×100)|
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| Discussion|| |
Two hundred and ninety-seven cases of thyroid diseases seen in this study constituted 1.1% of all specimens received in the department over the 10-year period of the study. It showed a female preponderance with a male-to-female ratio of 1:6. Studies by Nggada et al. in Ile-Ife, Nzegwu et al. in Enugu, Ijomone et al. in Port Harcourt, Nigeria, and Tsegaye and Ergete  in Adis Ababa, Ethiopia, showed comparable female preponderance of 1:6, 1:6.4, 1:10 and 1:4.5, respectively. A broad age range was observed in this study with a peak incidence in the fourth and fifth decades of life. However, studies by Ijomone et al., Nggada et al. and Tsegaye and Ergete  reported peak incidence in the third to fourth decades. This peak age incidence is significant in females because of the higher demand for iodine for physiologic needs in this age group. This also reflects and confirms the causal relationship between thyroid diseases and iodine deficiency.
Seventeen cases of thyroglossal cysts were seen and accounted for 5.7% of the total cases studied. One of the cases encountered in this study shows a cyst lined by respiratory type epithelium [Figure 4]. The peak age of occurrence was in the first decade of life with male-to-female ratio of 1:1.1. A study by Ijomone et al. showed frequency of 5.3% which is similar to our finding but with a higher male-to-female ratio of 1:6, while Nzegwu et al. reported a lower value of 1.8% and a ratio of 1:2.
Graves' disease (toxic goitre) represented 4.0% of all the cases analysed. This figure is slightly higher than reports of 1.5% from Port Harcourt, 1.4% from Ile-Ife and 0.91% from Karachi by Ijomone et al., Lawal et al. and Hussain et al. but comparable with reports of 3.1% in Enugu and 5.4% in Kano, respectively., The peak incidence was in the third decade with male-to-female ratio of 1:5.
Three cases of Hashimoto thyroiditis and a case of lymphocytic thyroiditis were seen in this study and accounted for 1.0% and 0.3% of all the cases, respectively. The three cases of Hashimoto thyroiditis were exclusively seen in females with peak incidence in the fifth decade while that of lymphocytic thyroiditis was found in a 26-year-old male. Other authors also found the prevalence of Hashimoto thyroiditis to be about 1% of all thyroid diseases in their series.,,,, Our finding is in conformity with several other studies within and outside Nigeria except for higher values reported for lymphocytic thyroiditis of 4.7% by Abdulkareem  from Iraq, 3.3% by Hussain et al. and 4.03% by Bukhari and Sadiq  from Karachi. These studies with higher values were notably reported outside the Africa continent. However, Ijomone et al. in Port Harcourt reported 0.8% which is comparable with our findings of 0.3%.
Colloid goitre [Figure 3] was the most common thyroid diseases encountered with 214 cases (72.1%). Nggada et al. in Ile-Ife, Southwest Nigeria, reported 75%, Ijomone et al. in Port Harcourt, South-South, 59.4%, Nzegwu et al. in Enugu, Southeast Nigeria, 63.2%, while Abebe and Osman  and Tsegaye and Ergete  both from Ethiopia reported frequencies of 80% and 76.9%, respectively. The higher percentages from Ethiopia may be due to iodine deficiency that characterise mountainous regions such as Ethiopia.
The peak age of occurrence for colloid goitre was the third decade with a male-to-female ratio of 1:9.2. This finding is comparable to the studies by Ijomone et al., Nzegwu et al., Nggada et al. and Tsegaye and Ergete. The male-to-female ratio of 1:18.8 in the study by Ijomone et al. in Port Harcourt doubles our ratio and that of Tsegaye and Ergete  (1:4.6) in Ethiopia. This high variation may be attributable to geographical location and socio-cultural factors such as diets rich in goitrogens.
Thyroid gland neoplasms accounted for 16.8% and were the second most common thyroid diseases seen in this study. Olatoke et al. in Ilorin, North-Central Nigeria, in their study reported comparable rate of 16.9%. Tsegaye and Ergete  and Ijomone et al. in their respective studies reported higher rates of 21% and 31.6%, respectively. These neoplasms showed a female preponderance as seen with majority of similar studies on the thyroid gland by Ariyibi and Duduyemi  in Ibadan, Ahmed et al. from Zaria, Olatoke et al. from Ilorin and Ijomone et al. in Port Harcourt. This female predominance is also seen in studies done in Karachi, Pakistan (1:3.6), and Ethiopia (1:2.9) by Bukhari and Sadiq  and Tsegaye and Ergete.
Benign thyroid neoplasms were generally more common than malignant ones and accounted for 72% of all neoplastic lesions studied with female-to-male ratio of 5:1. Previous studies from within and outside Nigeria have reported similar findings. The report from Basrah, Iraq, of 73.6% is in conformity with our finding, while Ahmed et al. reported 43% over a decade ago in Zaria; though the study covered a 20-year period, it was limited to neoplastic lesions alone. Low rates of 30.8%–43.7% were also reported in Ethiopia, Ile Ife  and Karachi. Comparable higher rates of 52.4% and 61% were reported from Port Harcourt and Adis Ababa, respectively.
Thyroid cancers constituted 4.7% of the total cases in this study. This rate is lower than many other studies both within and outside Nigeria. In Ile-Ife, Lawal et al. reported 12.9%, Nzegwu et al., 14.1%; Ijomone et al., 15%; Abdulkareem, 7.7% and Tsegaye and Ergete, 8.2%. The lower rate in this study may also be attributable to reduction in iodine deficiency in the general populace from scheduled treatment by government and thus a reduction in the incidence of follicular cancer. It could also be due to higher sample size and longer period in this study compared to these other studies. The female preponderance observed is similar to Ahmed et al.'s observation a decade ago in Zaria and studies by Ariyibi and Duduyemi  in Ibadan, Olatoke et al. in Ilorin, Ijomone et al. in Port Harcourt and Tsegaye and Ergete  in Ethiopia.
The highest frequencies of thyroid cancers in this study were in the third and fifth decades of life. There is a significant predominance of papillary carcinoma of the thyroid gland in our setting with a rate of 71.4%. Majority of the papillary carcinoma in this study occurred in the third decade, while the only two cases of follicular carcinoma were seen in the fifth decade. Ariyibi and Duduyemi  in Ibadan also reported papillary carcinoma as the most common malignant thyroid neoplasm though with a lower rate (41.8%) followed by follicular carcinoma (32.7%), with both cancers showing female preponderance as also seen in our study. Ijomone et al. reported 55% for papillary carcinoma and 30% for follicular carcinoma. Hussain et al. in Karachi reported a rate of 77.9% for papillary carcinoma and 12.6% for follicular carcinoma, similar to the findings in this study. Abdulkareem  in Basrah, Iraq, recorded 56.6% and 26% while Bukhari and Sadiq  in Pakistan reported 90.2% and 2% for papillary and follicular carcinoma, respectively. The decade-old earlier study from Zaria by Ahmed et al. also reported a higher rate 70.5% for papillary carcinoma in conformity with our finding of 71.4%. However, Edino et al. in Kano, Lawal et al. in Ile Ife, Olatoke et al. in Ilorin and Abebe and Osman  in Ethiopia reported follicular carcinoma as the most common thyroid cancer with rates varying from 44.4% to 92.9% and a female predominance. These contrasting findings may be attributed to the geographic influence of iodine deficiency and causal relationship with incidence of follicular carcinoma. The possibility of nonadherence to strict histological criteria in diagnosis of follicular carcinoma vis-a-vis adenoma may influence higher occurrence rates. In the United States, papillary carcinoma is the most common thyroid neoplasm and accounts for 75%–85% of cases, followed by follicular carcinoma which accounted for 5%. The global trend in the incidence of papillary carcinoma was demonstrated in our findings.
| Conclusion|| |
Thyroid diseases in Zaria showed a female predominance in the fourth and fifth decades of life. The most common diseases were colloid goitre, adenoma and papillary carcinoma.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
The initial draft of this work was presented as dissertation to the National Postgraduate Medical College of Nigeria for the award of fellowship in Pathology (FMCPath). I am sincerely grateful to the college.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]