Published in:
Open Access
01-12-2021 | Foreign Body Aspiration | Case Report
Diagnostic pitfall of thyroid fine-needle aspiration induced fibrosis: follicular adenoma mimicking medullary thyroid carcinoma in frozen section
Authors:
Woo Sung Moon, Myoung Jae Kang, Hyun Jo Youn, Kyoung Min Kim
Published in:
Diagnostic Pathology
|
Issue 1/2021
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Abstract
Background
Fine-needle aspiration (FNA) is a frequently utilized method for the diagnosis of thyroid nodules. Although the technique has clear advantages, the injury caused by the aspiration needle can induce various histological alterations. Herein, we report a case of follicular adenoma showing histological alterations possibly caused by FNA biopsy. Furthermore, the histological appearance of the lesion mimicked those of medullary thyroid carcinoma, particularly in the frozen section.
Case presentation
Ultrasonography of a thyroid nodule in a 39-year-old man revealed a mass (2.2 cm in diameter) in the right thyroid lobe. FNA was performed three times on the mass, and the results of the cytology were atypia of undetermined significance. Thereafter, the patient underwent right hemithyroidectomy. The histological findings of the operative frozen section analysis indicated medullary thyroid carcinoma. However, after evaluation and immunohistochemical staining of the permanent section, the mass was diagnosed as follicular adenoma with extensive fibrosis.
Conclusion
The histological alterations observed in the follicular adenoma are believed to have been caused by injury during the repeated FNA procedures.