Histopathological study of thyroidectomy specimens

Introduction: Diseases of thyroid gland are common and have wide spectrum of entities ranging from functional, immune mediated to neoplastic lesions. The aim of this study is to describe the different pattern of lesions in thyroidectomy specimens. Objectives: To study occurrence of various lesions of thyroidectomy specimens. Materials and Methods: This study was done in Dept. of pathology, Mysore Medical College over a period of 2 years from Feb 2017 to Feb 2019. The thyroid diseases were classified on histological grounds into congenital, nonneoplastic and neoplastic lesions that were further sub classified as benign and malignant as per WHO histological classification of thyroid tumors. Results: A total of 104 thyroidectomy specimens were received during this study period. 91 cases (87.5%) were females and 13 cases (12.5%) were males with F: M ratio of 7:1. Non neoplastic lesions accounted for 72% and includes colloid goiter, multinodular goiter, nodular hyperplasia, hashimoto’s thyroiditis, thyroglossal cyst and lymphocytic thyroiditis. Neoplastic lesions accounted for 30% and consists of follicular adenoma as benign neoplasm, 17 malignant cases, 13 cases were of papillary thyroid carcinoma classic type, two cases of follicular carcinoma, one case of well differentiated follicular carcinoma of undetermined malignant potential and one case of non invasive follicular tumor with papillary like nuclear features. Conclusion: Thyroid lesions predominantly affects females. Most commonly seen during 3rddecade of life. Colloid goiter is the commonest non-neoplastic followed by multinodular goiter. Follicular adenoma was the most common benign neoplasm, papillary carcinoma of thyroid was the common thyroid malignancy seen. © 2020 Published by Innovative Publication. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by/4.0/)


Introduction
The lesions of thyroid are very common worldwide and are commonly encountered in clinical practice. 1 Lesions of the thyroid may be developmental, inflammatory, hyperplastic or neoplastic. Enlargement of thyroid gland is relatively common and is known to affect 15% of population. 2 Enlargement can be diffuse, multinodular or solitary nodule. Surgery is usually done for the patients with solitary nodule because of suspicion of malignancy although malignancy is found only in 6-14% of solitary nodules. [3][4][5] Pathological lesions of thyroid gland are of importance because they affect function of other organs and are amenable to treatment which can be medical or surgical. Surgical excision and histopathological evaluation is very essential to establish a diagnosis. Most of thyroid nodules are benign and malignancy occur in approximately 5-20% of cases. Autopsy studies have shown that nodules in thyroid are very common and has been found in 50% of cases. Most of the thyroid nodules are benign and malignancy occur in 5% of cases. 6 Carcinoma of thyroid is relatively a rare tumor and incidence of carcinoma in multinodular goiter varies from 4% to 17%. 7 Increasing incidental thyroid cancer incidence has been attributed to improved imaging methods like radionuclide scanning and ultrasonography and successful surgical intervention. Hence present study was done to assess the histopathological diagnosis of 104 thyroidectomy specimens and evaluation of their frequency in relation to age and sex of the patient.

Materials and Methods
This was a retrospective study done for a period of 2 years from Feb 2017-Feb 2019. Total 104 thyroidectomy specimens were received which were fixed in formalin. Specimens were from lobectomy, hemithyroidectomy, near total thyroidectomy to total thyroidectomy. And these specimens were processed to make paraffin embedded tissue blocks and sectioned. All sections were stained with Haemotoxylin and Eosin. Slides were analysed taking into account of clinical, gross and microscopic details.
On gross examination, majority of the specimens were total thyroidectomies. 75% were diffusely enlarged, 20% had multinodular enlargement and 5% had solitary nodule.

Discussion
In the present study commonest age group presented with thyroid disorder was between 2 nd and 3 rd decade of life. While study carried by Fatima A. et al 8 found age incidence to be common in 3 rd and 4 th decade. Ramesh et al 9 found common age group from 3 rd to 5 th decade and Jagadale K.        (Table 5). Comparing the non-neoplastic lesions colloid goiter (32.6%) and multinodular goiter (27.8%), Hashimoto's thyroiditis (8%) were the common lesions.
Our present study correlated well with Jagadale K et al 10 with colloid goiter 21.4%, MNG 28.6% and Hashimotos thyroiditis 8.57%. Comparision with other studies for non neoplastic lesions is shown in Table 6.
Out of 29 cases of Multinodular goiter in our study, 2 cases showed incidental papillary carcinoma. Similarly, Jain et al found 3 cases of papillary microcarcinoma out of 35 cases operated for multinodular goiter. 11,12 Kumar    12 Hence thorough screening of all thyroidectomy specimens to rule out occult carcinoma as the risk of carcinoma in MNG is significant.

Conclusion
The present study was concluded with the following observations 1. Neoplastic and non neoplastic lesions were common in females 87.5%. 2. Common age group affected 2 nd to 3 rd decade. 3. Commonest non neoplastic lesion was Colloid goiter (32.6%) followed by multinodular goiter (27.8%). 4. Commonest benign neoplasm was follicular adenoma (13.4%). 5. Commonest malignant neoplasm was papillary carcinoma(12.5%). 6. The present study highlights the importance of histopathological typing of thyroid lesions for their better management. 7. All thyroidectomy specimens should be throughly grossed to rule out occult malignancy as the risk of carcinoma in Multinodular goiter is significant.

Source of Funding
None.

Conflict of Interest
None.