Introduction: Multifocal papillary thyroid microcarcinama (PTmC) has been considered as more aggressive than the unifocal one.
Aim of the study: This paper aims to compare this two groups considering histopatological sign of aggressivity, presence of inflammation and radioiodine uptake.
Materials and methods: The analysis concerned 81 patient with microcarcinoma (PTmC) selected from group of 961 (8%) diagnosed and treated in conventional way because of thyroid carcinoma. Patients were divided into three groups: S one focus, diameter ≤10 mm (n=45); MS multifocality, total diameter ≤10 mm (n=22); MB multifocality, total diameter >10 mm (n=14). Histopatology, level of anti-thyroglobulin antibody (a-TG) and radioiodine uptake were analized.
Results: Sensivity of FNAB was significantly lower in MS as compared to S or MB. Percentage of cases with capsules infiltration, angioinvasion and neck nodular metastases was the most highest in S respectively (62, 36, 11), MS (27, 18, 5) and MB (36, 7, 7). In multifocal cases capsules infiltration occurred more often in MB while angioinvasion was more frequent in MS. Both groups were similar in respect of neck nodular metastases presence. Presence of increased a-TG level was similar in S and MB but less frequent in MS while mean a-TG level was the highest in MS and lower but comparable in S and MB. Radioiodine uptake was comparable in all groups.
Conclusions: i) Inspite of the fact, that multifocality is believed to be associated with increased malignancy in analized group the signs of invasiveness were significantly more frequently observed in unifocal PTmC.
ii) Multifocality alone rather than total focuses diameter should be considered as a potential indicator of increased risk of invasiveness of PTmC.
iii) Relatively high incidence of multifocality may justify total thyroidectomy as a treatment of PTmC.