The Role of Cell Blocks and Immunohistochemistry in Thyroid Atypia of Undetermined Significance/Follicular Lesion of Undetermined Significance Bethesda Category

Abstract

<b><i>Introduction:</i></b> Thyroid cytology is a widely accepted tool in the clinical triaging of nodular lesions. Cell blocks (CBs) can help in the diagnosis of atypical lesions, namely, thyroid Bethesda category of Atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS). <b><i>Methods:</i></b> In a series of 224 AUS/FLUS thyroid samples with CB, we studied CB cellularity and feasibility of 3 immunohistochemical markers (cytokeratin 19 [CK19], HBME-1, and galectin-3) apart and in combination. <b><i>Results:</i></b> The CBs were non-diagnostic in 34 cases. Twenty-four CBs contained <10 cells, 45 CBs 10–50 cells, and 121 CBs >50 cells. Notably, more cellularity was found in CBs performed by plasma-thrombin and in-house techniques (<i>p</i> < 0.001). The diagnostic accuracy to detect malignancy was 65.1% for CK19, 72.1% for HBME-1, and 70.3% for galectin-3. <b><i>Conclusion:</i></b> In conclusion, CB cellularity is essential for successful immunohistochemistry application and further diagnostic workup of AUS/FLUS cases.

Cell block practices in European cytopathology laboratories

“…Moreover, orientation of a congealed cell pellet in the tissue cassette seems very important as well. Simply putting a congealed HistoGel 12 and salivary gland 13 FNAs, the Shandon/Epredia Cytoblock kit more often yields insufficient CBs than plasma and thrombin or in-house CB preparation methods.…”

“…However, it is only sporadically used in other countries. According to the studies on thyroid 12 and salivary gland 13 FNAs, the Shandon/Epredia Cytoblock kit more often yields insufficient CBs than plasma and thrombin or in‐house CB preparation methods.…”

The Contributory Role of Cell Blocks in Salivary Gland Neoplasms Fine Needle Aspirations Classified by the Milan System for Reporting Salivary Gland Cytology

“…In our setting, radiologists in training are widely involved in FNAs and, due to the learning curve, there are high rates within the insufficient category. Pre-analytical issues, including triaging of cytological material, are crucial steps in the cytological diagnostic work-up [8,28,29]. In thyroid gland AUS/FLUS categorized specimens, cytological material triaging had a diagnostic input [28].…”

“…Pre-analytical issues, including triaging of cytological material, are crucial steps in the cytological diagnostic work-up [8,28,29]. In thyroid gland AUS/FLUS categorized specimens, cytological material triaging had a diagnostic input [28]. In the present study, CBs were contributory to (crucial for or supporting) the diagnosis in 72.7% of AUS cases, 95.7% of benign neoplasm cases, 88% of SUMP cases, 66.7% of suspicious for malignancy cases and 50% of malignant neoplasm cases, respectively.…”

Immunohistochemistry in the pathologic diagnosis and management of thyroid neoplasms

“…TTF-1 can be useful in confirming the diagnosis of a thyroid primary lacking a well-differentiated growth pattern (papillary or follicular) or unusual cytology, such as poorly differentiated thyroid carcinoma, mucoepidermoid carcinoma, and secondary tumors ( 7 , 30 ).…”