Diagnosis of Thyroid Micropapillary Carcinoma and Histopathological Changes after Fine-needle Aspiration Biopsy.

Objective: To investigate "worrisome histologic alteration following fine-needle aspiration of the thyroid'' (WHAFFT) in thyroid papillary microcarcinoma and the importance of tumor size, fibrosis, depth and concomitant diseases in ultrasonographic diagno Place and Duration of Study: Department of Pathology, Kutahya Health Sciences University, Evliya Celebi Research and Training Hospital, Turkey, from December 2015 to December 2020.

Methodology: A total of 208 TPMC nodules belonging to 87 (41.8%) fine-needle aspiration biopsy (FNAB)-case group and 121 (58.2%) non-FNAB-control group were included in the study. The thyroidectomy specimens were evaluated for worrisome histologic alteration following fine-needle aspiration of the thyroid (WHAFFT). The relationship between tumor size, depth and capsule distance and concomitant diseases were investigated, according to the detection status in ultrasonography.

Results: In the FNAB group, hemorrhage, capsular distortion and tumor diameter were greater, while there was less non-tumor fibrosis and granulation tissue. Dysplasia focus was found to be higher in Hashimoto thyroiditis and lower in nodular goiter (p = 0.000). The rate of ≥0.5 cm tumors (p = 0.000), the rate of 0-25% tumor fibrosis (p = 0.038) and tumor-capsule distance between <0.2 cm (p = 0.030) was higher in thyroid micropapillary carcinomas detected in US.

Conclusion: In the FNAB group, hemorrhage, capsular distortion and tumor diameter were greater. While fibrosis was insignificant in the diagnosis with ultrasonography (US), tumor size and location were found to be more significant. Since US has a lower success rate in lesions <0.5 cm and is deeply located, it can be supported with radiological alternatives.

Key Words: Worrisome histologic alteration, Thyroid micropapillary carcinoma, Fine-needle aspiration, Ultrasonography.