Frequency of Malignancy in Multinodular Goitre

Objectives: To determine the frequency of thyroid carcinoma in clinically or sonogragraphically multinodular goitre in patients undergoing thyroidectomy Setting: This is a cross sectional study was carried out at the Department of Otolaryngology and Head-Neck Surgery, Bangabandhu Sheikh Mujib Medical University during the period from January 2012 to June 2012. Methods: This study includes all the patients admitted in Otolaryngology and Head-Neck surgery department of Bangabandhu Sheikh Mujib Medical University having diagnosis of multinodular goitre & underwent thyroidectomy. All patients with non-toxic multinodular goitre (clinically or sonographically) irrespective of age , sex was be included . Results: Out of 50 patients, 41 patients (82%) were female, and 9 patients (18%) were male with a female to male ratio 4.5: 1. This shows female preponderance of multinodular goitre. Out of 50 patients, 5 patients had histologicaly proven thyroid malignancy (4 females and 1 male). In this study overall incidence of carcinoma in multinodular goitre was 10% and female to male ratio 4:1 with the incidence in female was 9.75% and in male 11.11. The incidence of malignancy under 21 years was 50% and above 21 years was 8.33%. Regarding the types of malignancy in this series, papillary carcinoma was the most common variety (80%) followed by follicular carcinoma (20%).


Introduction
Thyroid gland is one of the most common endocrine gland to be affected by various disease processes.It is the largest gland in endocrine family.
Goitre meaning throat (French) and English scientists described goitre in 1625 1 .Thyroid cancer was first described in 1811 by Burn.Interest in the etiology and prevalence of thyroid cancer arose around 1940 when high incidence of thyroid cancer was found in post thyroidectomy patients. 2yroid carcinoma is a relatively rare tumor, but represents the most frequent form of cancer of the endocrine glands .It may either as a solitary nodule or as a dominant nodule in a multinodular goiter.It represents 1%of human neoplasias and its annual incidence is estimated world wide from 0.5 to 10 :100,000 subjects in the world population .24] The annual incidence of thyroid carcinoma varies considerable in different registries and is increasing in some European countries, USA and Canada. 5, multinodularity of the goitre should not be considered as low risk of malignancy and delay for surgical intervention .Changes in the size of gland, the appearance of new and hard nodules or cervical lymphadinopathy may indicate malignant change and promt indication for surgery .In this study, out of 50 patients 41 patients (82%) were female and 9 patients (18%) were male, with female to male ratio 4.5:1.Female preponderance also found in other studies that was firmly consistent with this studies. 7l the patients in this series presented with neck swelling (painless) of varying durations.Out of them, 3 patients in addition to neck swelling had pressure symptoms (dyspnoea, dysphagia).

Methods
Among the indications for thyroidectomies in this series enlarged thyroid (multinodular goitre) is the most common one, 44 patients (88%) were operated upon this indication, 3 patients (6%) were operated for pressure symptoms and 3 patients (6%) were operated for malignancy 10][11] In this series, out of 5 patients of thyroid malignancy, only one patient (female) was below 21 years of age and the other 4 patients (1 male and 3 females) were above 21 years of age.The incidence of malignancy under 21 years was 50% and above 21 years was 8.33%.Another study also found that the incidence of malignancy was 11.7 years under 21 years of age and 7.5% above 21 years. 12,13lignancies associated with multinodular goitre are usually follicular or papillary carcinoma. 14In the study, out of 107 patients of multinodular goitre 7.5% harboured foci of malignancy with papillary carcinoma being the most common variety 8 .In another study, 75% of carcinomas occurring in multinodular goitre were of papillary type 12 .In another study also found an almost equal ratio of papillary to follicular carcinomas in the patients with malignancy occurring with multinodular goitre (11 papillary to 9 follicular). 10wever the incidence of papillary carcinoma to other carcinomas of thyroid gland is relatively higher in different studies. 11,15 this study, out of 50 patients FNAC positive for malignancy in 3 cases but histopathology positive for malignancy in 5 cases.FNAC sensitivity 71.42%.
Those patients in this series who had malignancy in multinodular goitre, the mean duration of presenting symptoms was 10.2 years (minimum 6 years and maximum 13 years) and those patients who had only multinodular goitre, the mean duration of presenting symptoms was 5.91 years (minimum 2 years to maximum 14 years).In their study found that patient with malignancy in multinodular goitre had neck swelling for a longer period, 9.11 years as compared with a mean of 5.48 years for those with only multinodular goitre 10 .It is evident that the longer the duration of multinodular goitre the higher the chance of malignancy.The types of thyroidectomy performed were -subtotal thyroidectomy in 40 cases, hemithyroidectomy in 0 case and near total thyroidectomy in 7 cases and total thyroidectomy in 3 malignant cases.

Conclusion
The association of multinodular goitre and thyroid carcinoma should always be carefully considered.Multinodular goitre can not be considered as a condition predisposing to cancer but it may harbor cancer .Papillary carcinoma is relatively common variety.Female to male ratio, those with only multinodular goitre is 4.5:1 while in those with carcinoma in multinodular goitre is 4:1.This indicates males with multinodular goitre have higher chance of developing malignancy.Malignant chance is more in earlier age group.
Longer the duration of presentation , chances of malignancy is higher.

Table - V
Preoperative fine needle aspiration cytology findings