Core Needle Biopsy Can Early and Precisely Identify Large Thyroid Masses

Abstract

Background: Large thyroid masses, particularly if rapidly growing, are often characterized by compression and infiltration of the vital structures of the neck. Therefore, an early and precise diagnosis, not only of malignancy but also of histotype, is mandatory to set up the right therapy. The aim of this study was to evaluate the diagnostic performance of fine needle aspiration cytology (FNAC) and core needle biopsy (CNB) in this setting.

Patients and methods: We prospectively evaluated 95 patients with large and rapidly growing thyroid masses admitted to the University Hospital of Pisa between April 2014 and January 2020. All patients were submitted to FNAC and CNB in the same session. The ability of both procedures to diagnose the malignancy of the lesions, particularly the histotype, and to obtain sufficient material to perform molecular analysis was evaluated.

Results: FNAC obtained adequate tumor sample to reach a diagnosis in 76 of 95 (80%) patients, while a higher percentage was obtained with CNB (92/95, 96.8%). FNAC was able to identify the malignancy of the lesion in 74 of 95 (77.9%) cases, but only in 16 of 74 (21.6%) cases was it able to define the histotype. CNB was able to define the malignancy of the lesion in all but three cases (92/95, 96.8%), and in all specimens, the histotype was identified. Moreover, in all cases, the material extracted from CNB was optimal to perform molecular analysis. No surgery-related complications were experienced with both procedures.

Conclusions: CNB is a rapid and safe procedure with higher performance compared to FNAC in identifying the histotype of large and rapidly growing thyroid masses. Moreover, adequate material can be obtained to characterize the molecular profile for the treatment of potentially lethal cancers. In the era of precision medicine, CNB should be introduced in routine clinical practice as a key procedure for an early diagnosis and therapy of these diseases.

Keywords: anaplastic thyroid carcinoma; core needle biopsy; fine needle aspiration cytology; poorly differentiated thyroid carcinoma; thyroid lymphoma.

Figure 1

Correlation of the results of CT scan with those of fine needle aspiration cytology (FNAC), core needle biopsy (CNB), and specific immunohistochemical staining for anaplastic thyroid carcinoma (ATC), poorly differentiated thyroid cancer (PDTC), thyroid lymphoma (TL), and thyroid gland metastases (TGM) of lung adenocarcinoma. (A) Representative cytological and histological images of a case of ATC. (A1) CT scan with i.v contrast imaging. (A2) FNAC sample showing a few isolated atypical cells in a necrotic background (original magnification, ×40; Papanicolaou staining). (A3) CNB provided a tissue fragment composed of malignant undifferentiated neoplasia (original magnifications, ×4 and ×10; H&E staining). (A4) Immunohistochemical staining showing neoplastic cells with a high proliferative index, immunoreactivity for vimentin, and patchy weak immunopositivity for cytokeratins. (B) Representative cytological and histological images of a case of poorly differentiated thyroid carcinoma. (B1) CT scan with i.v contrast imaging. (B2) FNAC sample showing numerous groups of follicular cells with moderate nuclear atypia (original magnification, ×10; Papanicolaou staining). (B3) CNB showing neoplastic cells arranged in solid and trabecular architecture (original magnifications, ×4 and ×10; H&E staining). (B4) Immunohistochemical staining showing focal weak immunoreactivity for thyroglobulin and diffuse immunoreactivity for TTF-1 and PAX8. (C) Representative cytological and histological images of a case of TL. (C1) CT scan with i.v. contrast imaging. (C2) FNAC sample not diagnostic for the presence of extensive crush artifacts (original magnification, ×20; Papanicolaou staining). (C3) CNB provided a fragment of tissue composed of muscular tissue with intense lymphoid infiltration (original magnifications, ×4 and ×10; H&E staining). (C4) Immunohistochemical staining showing that neoplastic cells were CD20 positive and CD3 negative with high proliferative indices compatible with B-cell lymphoma. (D) Representative cytological and histological images of a case of carcinoma of extra-thyroid origin. (D1) CT scan with i.v contrast imaging. (D2) FNAC sample showing a few groups of epithelial cells with marked nuclear atypia (original magnifications, ×10 and ×40 in the insert; Papanicolaou staining). (D3) CNB showing a few clusters of neoplastic cells interspersed in fibrotic stroma (original magnifications, ×4 and ×10; H&E staining). (D4) Immunohistochemical staining showing the absence of immunoreactivity for thyroglobulin, TTF-1, and PAX8, suggesting an extra-thyroid origin.

Figure 2

Diagnostic ability of fine needle aspiration cytology (FNAC) and core needle biopsy (CNB) in identifying tumor histotype.