Endocrine Abstracts

Background and objective: The incidence of differentiated thyroid carcinoma (DTC) is increasing worldwide. Due to a increased use of improved radiological techniques, especially ultrasound. This study aims to analyze histological characteristics of DTC diagnosed in our hospital in the last fifteen years.

Patients and methods: It is a restrospective descriptive study. We have included all operated patients in our center between 2001 and 2015 with a final biopsy of DTC. We have analyzed three main variables. Ultrasound guided fine needle aspiration (FNA) cytology previous surgery: insufficient (Betestha I) benign (Betestha II), undetermined (Betestha III,IV,V) and malignant (Betestha VI). Histological type: Papillary Thyroid Carcinoma or Folliculary Thyroid Carcinoma and variants. Size of tumor.

Results: A total of 187 patients were diagnosed of DTC, 78.7% were women with a mean age at diagnosis of 49.47±15.88 years. Ultrasound-FNA cytology was malignant (Betestha VI) in 33.1% of patients, undetermined (Betestha III, IV,V) in 43.4% of patients, benign (Betestha II) in 13.9% of patients, insufficient (Betestha I) in 9.6% of patients. In 22 cases ultrasound-FNA wasn’t performed. Papillary Thyroid Carcinoma accounted for 91.5% of cases, whose main subgroup correspond to Classical variant (40.1%) followed by Microcarcinoma (28.5%) and Encapsulated (22.1%) Follicullary Thyroid Carcinoma was found in 8.5% of cases, mayor subgroup was the Minimally Invasive (50%) followed by Hurtle (37.5%). The comparison between preoperative cytology and final biopsy showed that 63.6% of malignant cytologies correspond to Classical Papillary. And 52.2% of benign cytologies are Microcarcinoma Papillary in final biopsy. Undetermined cytologies in the end were classified as 29.2% Classical Papillary, 27.8% Encapsulated Papillary, 23.6% Microcarcinoma Papillary. Statistic difference was found in all groups (P=0.08). Most tumors have a size between 1 and 4 cm (52.1%). Under 1 cm 36.7%. Tumor size has been decreasing with the pass of years. In 2001 it was 28±6.1 mm and in 2015 it was 17.16 mm ±13.1 mm. No statistic significance was found in any group.

Conclusion: According to the literature, the most common CDT type is Papillary. However, the amount of Microcarcinoma and Classical variant is very similar in literature data, around 33%. But in our center Classical variant is the most frequent. Tumor size is lower at the end of follow-up with no statistic differences. As further studies are needed to reach a bigger population.