Fine needle aspiration cytology of thyroid swellings : Experience in a tertiary care hospital of Nepal

Introduction: Fine Needle Aspiration Cytology (FNAC) being a minimally invasive technique, is particularly suitable in the sensitive neck area. FNAC can obviate the need for surgery if the lesion is shown to be non neoplastic or if it confirms suspected recurrent tumor. A preoperative cytological diagnosis of a primary neoplasm of thyroid may allow more rational planning of surgery. Method: This descriptive observational study was carried out at the Department of ENTHead & Neck Surgery, Gandaki Medical College and Charak Hospital, Pokhara, Nepal, from August 2010 to November 2011. A total of 154 consecutive FNAC of thyroid swellings was included. Results: Out of 154 patients female were 142 (92%) and men were 12 (8%). In this series of 154 thyroid swellings on FNAC one hundred and thirty six (88%) were non neoplastic and eighteen (12%) neoplastic. Among non neoplastic thyroid swelling, adenoma was the most common sixty two (40%), followed by colloid cyst, Hashimoto thypoiditis, subacute thyroiditis, adenoma, cystic lesion, Graves’s disease, thyroglossal cyst and lymphocytic thyroiditis. Among neoplastic thyroid swelling papillary carcinoma was the commonest nine (5.8%) followed by follicular neoplasm six (3.9%). Conclusion: It is concluded from the present study that female in our region were more affected, non-neoplastic lesions of the thyroid were more common (colloid goiter being the commonest) than neoplastic lesions (papillary carcinoma being the commonest).


Introduction:
Fine needle aspiration cytology (FNAC) is simple, less expensive, readily available and reliable, time saving, easy to perform, effective and almost accurate diagnostic technique for investigation of thyroid swellings.The prevalence of thyroid swellings ranges from 4% to 10% in the general adult population and from 0.2% to 1.2% in children 1 .The majority of clinically diagnosed thyroid swellings is nonneoplastic; only 5%-30% are malignant and require surgical intervention 2 .Laboratory investigations other than FNAC have limited role to find out the nature of thyroid swelling.Isotope scan can demonstrate the functioning capacity of the nodule but cannot predict the cytopathological character.Ultrasonographic scanning is

Original Article
Bangladesh J Otorhinolaryngol 2012; 18(2): 119-123 capable of differentiating solid from cystic lesions but cannot distinguish neoplastic from nonneoplastic one.FNAC of the thyroid is gaining popularity among the pathologists and clinician.It is the initial investigation in the management of thyroid disease in our center.However, this study is aimed at evaluating our experience of FNAC in thyroid swellings.

Methods:
A Cross sectional study was done in the Department of ENT-Head & Neck Surgery, Gandaki Medical College and Charak hospital, Pokhara, Nepal, from August 2010 to November 2011.All patients were evaluated by thorough clinical examination followed by routine investigations, thyroid function tests and FNAC.Apparatus used included 10 ml disposable plastic syringe 22-25 gauge, 0.6-1.0mm external diameter disposable needle 3.98 cm and 8.8 cm long with or without stylet, antiseptic sponges, sterile gauze pads, microscopic glass slides.
All FNACs were carried out by the pathologists.A 23-gauge needle was connected to a 10-ml syringe mounted on a syringe holder.Multiple needle passes were made within the lesion 3-4 times at varying angles and depths and with constant negative pressure (never emerging outside the skin).Before final withdrawal, the negative pressure was released prior to the needle emerging from the skin.The cytological material was transferred onto glass slides.The aspirated material then smeared on 2-4 slides, fixed in 95% ethanol and stained by papanicoloau and May -Grunwald Giemsa stains and was evaluated by the pathologist for cytology.The data analysis was performed using SPSS version 17.

:
Figure 1: Age distribution of thyroid swelling.

Discussion:
Fine needle aspiration cytology is regarded as the gold standard initial investigation in the diagnosis of thyroid swellings 3 .The is safe simple and quick with a low complication rate and helps to select people preoperatively for surgery 4 .Carcinoma of the thyroid is the most common malignancy of endocrine system comprises 0.6% and 1.6% of all cases of malignant neoplasm in men and women respectively.
In the present study, the age of patients ranged from 7 to 88 years with a mean of 43.95 and SD±15.70 years.This age range and mean incidence is slightly lower as compared with previous studies 5,6 .We found that majority of patients in our study (42%) were in their fourth to sixth decade of life while in the study by Dorairajan and Jayashree 44% were in the third decade of life 7 .
In the study by Md.Shafiqul Islam, most of the patients were between 21 to 40 years age group (60%).Mean age 37.70, (SD±10.05)years.Lower limit of age was 18 years and the highest age was 60 years.Twenty six (28.88%) male and sixty four (71.12%) female.Representing Male:Female ratio 1:2.46 8 .Comparing this to the present study female were higher in frequency (n=142 ; 92% ) than men (n=12 ; 8%) and the male: female ratio was 1:12.

121
Fine needle aspiration cytology of thyroid swellings R Nepali et al Among thyroiditis Hashimoto thyroiditis was most common seventeen (11%) followed by sub-acute thyroiditis twelve (7.8%).FNAC contributes significantly to the pre-operative investigation in patients with thyroid swelling but despite its well recognized value there are limitations to the technique.The first such drawback of FNAC is the high inadequate sample rate 12,13 .The second major limitation of thyroid cytology is its inability to distinguish a follicular adenoma from follicular carcinoma [13][14][15][16] .This diagnosis requires detailed histological examination for vascular or capsular invasion and cannot be reliably made on routine FNAC specimens [17][18][19][20]

Figure 2 :
Figure 2: Sex distribution of thyroid swelling.

Table - I
FNAC diagnosis of non neoplastic thyroid swelling (n=136).

Table - III
Comparison of results of present study with previous studies:

Table - IV
Comparison of Incidence of types of thyroid swelling by FNAC: