Our experience with papillary thyroid microcancer

Abstract

Background:Papillary thyroid microcarcinoma (PTMC) describes a focus of papillary thyroid cancer that is less than 1 cm in size. These tumors are frequently found on histopathological examination of thyroid specimens, operated upon for an indication other than suspected malignancy.Materials and Methods:From 2005 to 2012, 94 of 1300 thyroidectomy specimens in our institution were found to have PTMC. Of these, 77 were isolated PTMC while the others were associated with other differentiated cancers. We studied their clinicopathologic features, treatment and long-term outcome.Results:There were 18 men and 59 women (the male: female ratio was 1:3), their mean age was 44 ± 10.5 years (range: 18-72 years). Multinodular goiter was the most common indication for surgery. Malignancy was suspected in only 31.4% cases. The mean tumor size was 4.1 ± 2.3 mm. Nearly 17% cases had slightly larger tumors measuring >6 but <10 mm. Multifocal tumor was found in 44.1% of cases and among these, multifocal disease restricted to a single lobe was found in 19.5%. Eleven patients (14.2%) had cervical lymph node metastasis, 3 (3.9%) had extra thyroid tumor extension and 2 (2.6%) had evidence of vascular invasion. One patient (1.3%) presented with bone metastasis. Majority of the patients (79.2%) underwent total thyroidectomy with or without lymph node dissection. Sixteen patients (20.7%) who had initially undergone hemithyroidectomy went on to have completion thyroidectomy. Twenty nine patients (36.8%) also received radioactive iodine. The mean duration of follow-up was 20.2 ± 13.5 months. On follow-up one patient developed cervical lymph node recurrence and one died due to a second malignancy.Conclusions:PTMC is often found as an incidental finding on the thyroidectomy specimen. Sometimes they present with regional lymph node metastasis and very rarely with distant metastasis. They have a good prognosis similar to papillary thyroid carcinoma.

Incidental Papillary Thyroid Microcarcinoma in an Endemic Goiter Area

“…Our incidence rate of 18% for the presence of two or more foci in the gland and the rate of 20% for the location of tumour foci in both lobes confirmed the pathological features of incidental PTM. Previous studies have also reported the multifocality rate of I-PTM to be between 13% and 44.1% [ 7 – 9 , 15 – 19 ]. Some studies have reported multifocality as an independent risk factor for tumour recurrence [ 6 , 8 , 11 , 14 , 18 , 20 , 21 ].…”

“…In another study, the proportion of PTM in papillary thyroid cancer cases was determined to be 49%, of which 58% were incidental [ 8 ]. The proportion of incidental cases among all PTM cases was found to be between 49% and 75.5% [ 8 , 11 – 15 ]. Londero et al [ 5 ] recently reported that age-standardised rates increased from 0.35 per 100,000 per year in 1996 to 0.74 per 100,000 per year in 2008.…”

Incidental thyroid carcinomas. A retrospective study

“…Concerning associated thyroid diseases, multinodular goiter appear to have the highest incidence, from 4% to 17% (43,44). In Graves, the incidence varies from 0.5% to 1.8% (45)(46)(47)(48)(49).…”

Should the Prevalence of Incidental Thyroid Cancer Determine the Extent of Surgery in Multinodular Goiter?

“…In this particular study, the authors observed the patients for approximately 180 months. Many researchers have emphasized the disadvantage of leaving thyroid tissue in the operative bed after subtotal thyroidectomy [21–24]. They have suggested that in the future, some of these patients may require reoperation due to ITC in recurrent goiter, which may be associated with a worse prognosis and a higher rate of complications compared with patients who have received primary surgery [21–23].…”

“…They have suggested that in the future, some of these patients may require reoperation due to ITC in recurrent goiter, which may be associated with a worse prognosis and a higher rate of complications compared with patients who have received primary surgery [21–23]. John et al [24] examined 1300 thyroidectomy specimens for the presence of incidental papillary thyroid microcarcinoma. These authors noted that the most common indication for surgery among this group of patients was MNG with consideration of the ITC prevalence.…”