Introduction
Thyroid gland in the adults is the largest of all endocrine glands and embryologically it is the first to develop in fetal life. It is known to undergo various disorders ranging from developmental to acute, subacute and chronic inflammatory processes, hyperplastic changes and neoplastic disorders as well.1 Incidental asymptomatic lesions are also common in the thyroid gland. Due to better availability of ultrasound (USG) in the present days, almost 33% to 68% of such thyroid nodules are detected by USG. Detecting thyroid nodules on physical examination is possible only when they are a little large and just 4% of cases are picked up by palpation. Meticulous autopsy can detect thyroid lesions up to a tune of 50%.2, 3, 4, 5 Overall, in the general population, almost 4% to 10% adults may have thyroid lesions whereas, in the paediatric population the prevalence of thyroid lesions is 0.2% to 1.2%. Almost 95% of thyroid swellings are benign, but some pointers in patient history, laboratory, and sonographic findings can point towards malignancy.6 It is difficult to distinguish between the benign and malignant nodules solely based on patient history. However, whenever there is a history of irradiation to head and neck region, especially in childhood, followed by thyroid lesion, one has to be very cautious as irradiation is a predisposing factor for thyroid malignancy. The risk of carcinoma in such nodules is very high, almost 35% to 40%, whereas, in the general population such risk is just 5%.7 Many diagnostic modalities like ultrasound, thyroid nuclear scan, fine needle aspiration cytology (FNAC) are useful to assess goitre. Most often a definitive diagnosis mandates a morphological examination of lesions for which FNAC and histopathological examination (HPE) become more important.8 Thyroid fine-needle aspiration cytology (FNAC) began in 1950 and has been widely used since then.9 In the present day, it is a well-accepted technique for pre-operative diagnosis of thyroid pathology. Diagnosis based on thyroid FNAC is extremely useful as it segregates the benign lesions from malignant ones and thereby helps in obviating unnecessary surgery. 10 Thyroid cytology can provide a near-definite diagnosis. It can triage the remaining patients into those who potentially require surgical approach as opposed to medical/endocrinological treatment.11 Thyroid cytology is useful for diagnosis as well as for guiding treatment approach.12
Aim of the Study
To evaluate cytology and histopathology correlation of thyroid swellings in a teaching hospital.
Materials and Methods
There were no ethical issues involved in our study.
Written informed consent was taken from all the patients included in the study.
This was a prospective study conducted in the department of Pathology at VRK Medical College for a duration of two years from April 2019 – March 2021.
Total of 55 cases of thyroid swelling were included in this study.
Inclusion criteria
All patients with thyroid swellings, who underwent FNAC (Fine needle aspiration cytology) followed by its subsequent Histopathological examination.
Methodology
A questionnaire was prepared and all the demographic characteristics were noted including age, gender, history of present illness, personal history, and history of any drug intake. A thorough clinical examination of neck was done and followed by routine investigations including complete blood counts (CBP) and complete urine examination (CUE). Values of thyroid function tests, serum T3, T4, and TSH levels were noted. Ultrasonography of neck was done in the department of Radiology on Toshiba machine.
FNAC was done in all the patients with thyroid swelling included in the study under all aseptic measures and slides were prepared and stained with hematoxylin and eosin stains (H&E) and Papanicolaou stain. FNAC Slides were reported. For histopathological examination, thyroid specimens (subtotal thyroidectomy, total thyroidectomy and lobectomy) were sent from the department of general surgery to the pathology department. Thyroid specimens were fixed in 10% formalin, processed and embedded in paraffin. Sections were cut on microctome (Leica) and slides were made and stained with H&E. IHC markers done wherever needed.
The cytology reports were compared with the histopathological diagnosis.
Results and Observations
Table 1
Age-wise distribution
|
Age distribution (years) |
No. of cases |
Percent (%) |
|
10-20 |
02 |
3.6% |
|
21-30 |
07 |
12.7% |
|
31-40 |
09 |
16.3% |
|
41-50 |
32 |
58.1% |
|
51-60 |
03 |
5.4% |
|
61-70 |
02 |
3.6% |
|
Total |
55 |
100% |
The age distribution ranged from 10 -70 years. Most of the cases were noted among 41-50 years (58.1%), followed by 31-40 years (16.3%).Table 1
There were 40 (72.7%) female patients and 15 (27.2%) male patients and the male to female ratio was 1:2.6.
Table 2
Clinical symptoms
Duration of symptoms: In the present study, duration of symptoms was less than one month in 4 (7.2% cases); it was 1 month to 1 year in 37 (67.2%) cases; 1 year to 2 years in 5 (9%) cases and more than 2 years duration was seen in 9 (16.3%) cases.
Table 3
Distribution of cases on FNAC
On FNAC, non neoplastic lesions constituted 83.3% (46/55) cases and nodular goiter was the most commonly reported entity.
Table 4
Distribution of cases on histopathological examination (HPE)
On histopathology, nodular goiter was the most commonly reported diagnosis and constituted 45.4% (25/55) cases.
Table 5
Cytology and histopathology correlation
Suspicious for malignancy were considered as malignant on cytology.
In our study, FNAC had a Sensitivity of 62.5%, and Specificity of 100% to detect thyroid malignancy. The Positive predictive value and Negative predictive value were 100% and 97.9% respectively.
Discussion
In the present study, 55 cases of thyroid lesions were compared for cytology and histopathology.
Comparative studies related to age distribution
In the present study age distribution ranged from 10 -70 years. Majority were noted among 41-50 years (58.1%), followed by 31-40 years (16.3%). This was compared with various other studies. In the study by Sirry MA et al13 the age ranged from 15 to 79 years, with a mean of 45.36 years. Most were found in the fourth and fifth decades of life (55%). In Santosh et al 14 study, the age of the patients ranged from 19 years to 60 years with mean age of 39.5 years. In Borgohain et al study 15 most of the patients were in age group of 21-40 years.
Comparative studies related to gender distribution
In the present study, females (72.7%) out numbered males (27.2 %). In a study done by Abhay Kumar et al16 the thyroid lesions were common in women than men with 6.02:1 ratio. In Santosh et al14 study, 34 (92%) were females and 3 (8%) were males. In Raniwala et al17 study, the ratio of female : male was 5.7:1. The proportion of males was 9 (15%) as compared to females 51 (85%). In Borgohain et al15 study, females (109 patients, 89.34%) were higher in frequency than males (n=13; 10.66%). In Sirry et al13 study, 80 (80%) patients were females and 20 (20%) patients were males, with female to male ratio of 4:1. Our findings of gender distribution compare well with all the above studies.
Comparative studies related to clinical presentation
In the present study, 32.7% presented with solitary nodule thyroid, 29% Multinodular goiter, 12.7% diffuse thyroid swelling, 14.5% multiple nodules + difficulty in swallowing+pain in throat and 10.9%+ solitary nodule thyroid+ Difficulty in swallowing+ pain in throat. In a study conducted by Raniwala et al 17 out of 60 cases, 34 (56.67%) were unilateral, followed by 15 (25%) cases with bilateral complaints and 11 (18.33%) cases were of solitary thyroid nodule (STN). Kumar et al 16 in their study observed that swelling in front of the neck was most common presentation and was seen in 98.98% (n=293) cases followed by dysphagia seen in 17.97% (n=53) cases.
Comparative studies related to duration of symptoms
In the present study, 67.2% presented with symptoms of 1month to 1 year and 16.3% had > 2 years duration and 9% cases had duration of 1-2 years. In a study done by Raniwala et al 17 majority of the cases, i.e., 30 (50%) cases had swelling for 1 to 4 years, while there were 17 (28.33%) cases who had thyroid swelling for less than one year, followed by 10 (16.67%) cases with duration of 4 to 7 years. In Kumar et al16 study, most of the patients (32.88%) had symptoms lasting for over more than one year.
Comparative studies related to FNAC
In our study, non neoplastic lesions constituted 83.3% (46/55) cases on FNAC. Among non neoplastic lesions, nodular goiter was most commonly reported and constituted 49% cases, autoimmune thyroiditis 18.1% cases, and colloid goiter16.3% cases. Neoplastic lesions constituted 16.2% and among neoplastic lesions, Follicular neoplasm occupied 7.2%, Suspicious of malignancy were 5.4% cases, and Malignancy was reported in 3.6% cases. In a study conducted by Kumar et al16 FNACs showed colloid goitre in 65.4% cases. Six cases were reported as follicular neoplasm on FNAC. Two cases were in the ‘Suspicious for malignancy’ category. In Disha J et al18 study, amongst non-neoplastic lesions, colloid goiter (71.5%) was most common, followed by lymphocytic thyroiditis (14.6%) and least common was acute thyroiditis (1.5%) cases. Among neoplastic lesions based on FNAC, follicular neoplasm consisted 89.2% cases, papillary carcinoma thyroid (PTC)) was 6.1% cases, anaplastic carcinoma was 4.6%) cases and least was Hurthle cell neoplasm, 1.5% cases. In Raniwala et al17 study maximum cases were diagnosed as multinodular and colloid goiter. Eight out of 60 cases were diagnosed as being malignant (follicular, papillary, and medullary carcinoma). Rout et al19 observed colloid goiter to be most common among thyroid lesions (42.2%) followed by colloid goiter with cystic degeneration (13.2%). In Santosh et al14 study, FNAC results showed benign lesions in 34 (92%) patients [Multinodular goiter in 12 (32.4%) cases, Hashimoto thyroiditis in 9 (24.3%) cases, Follicular adenoma in 6 (16.2%) cases, Colloid goitre with cystic change in (13.5%) cases, Haemorrhage in 2 (5%) cases] and Malignant lesions in 3 (8%) patients [ PTC in 2 (5.4%) cases and Colloid goiter with follicular neoplasm in 1 (2.7%) case.
Comparative studies related to histopathological examination
In the present study, nodular goiter was most commonly reported on histopathology and constituted 45.4% cases, autoimmune thyroiditis 12.7%, Lymphocytic thyroditis in 5.4%, colloid cyst in 7.2% and colloid goiter in 16.3% cases. Follicular adenoma occupied 9.09%, 7.2% as PTC and 3.6 % reported as Follicular carcinoma. In Disha J et al 18 study, colloid goiter 79.1% was the most common diagnosis, followed by thyroid cyst in 11.9% cases and least common was lymphocytic thyroiditis seen in 1.5% cases. On histopathology, follicular adenoma 38.4% was most common, followed by papillary carcinoma 30.7% cases, and follicular carcinoma 15.3% cases. Least common lesions were 7.69% each of Hurthle cell adenoma and undifferentiated carcinoma. In Santosh et al14 study, histopathology revealed benign lesions in 34 (91.8%) patients. Multinodular goiter was seen in 32.4%, Hashimoto thyroiditis in24.3%, Follicular adenoma in 16.2%, colloid goiter with secondary changes in 10.8% cases. PTC was seen in 8.1%) patients. Borgohain et al15 reported on histopathology 92 (75.40%) cases as non-neoplastic and 30 (24.5%) as neoplastic. Within the non-neoplastic diagnoses, colloid goiter was the most common 41%, nodular goiter was 18%, MNG was 7%, Hashimotos thyroiditis was 5%, benign haemorrhagic cyst was 2.4%, and one case each of benign colloid cyst and chronic thyroiditis was seen. In the neoplastic group, PTC was the most common with 10% cases, follicular adenoma with 9 cases, follicular carcinoma 5 cases and medullary carcinoma with 4 cases. In Sirry et al13 study, the postoperative histopathological examination revealed 75 (75%) benign cases: 13 (13%) colloid nodules, six (6%) adenomas, 22 (22%) simple MNG, 29 (29%) toxic MNG, and five (5%) cysts. A total of 25 (25%) cases were malignant: 15 (15%) were papillary carcinoma, five (5%) follicular carcinoma, two (2%) medullary carcinoma and three (3%) anaplastic carcinoma.
Non neoplastic lesions were more commonly reported in above comparative studies as well as in our study.
Comparative studies related to statistics
In our study, results showed Sensitivity of 62.5%, and Specificity of 100% for malignancies on FNAC. Positive predictive value and Negative predictive value were 100% and 97.9% respectively. In the study conducted by Santosh et al 14 results showed Sensitivity of 66.66%, and Specificity of 97.65%. Positive predictive value and Negative predictive value were 66.66% and 97.65% respectively.
Conclusion
FNAC is a minimally invasive, low cost testing modality. It accurately diagnoses malignant thyroid lesions. It has good specificity and accuracy but is less sensitive in diagnosing definitive etiology. However, it is an important diagnostic test to guide the management of thyroid lesions.
