Characterization of “Suspicious for Malignancy” for Non-Papillary Carcinoma Diagnoses on Thyroid Fine-Needle Aspiration.

Abstract Objectives To evaluate the incidence, risk of malignancy and management of “Suspicious for Malignancy (SFM) for non-papillary carcinoma diagnoses according to The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). Materials and Methods A retrospective search was performed for all thyroid fine-needle aspirations (FNAs) with an SFM diagnosis in the electronic Pathology database at The Johns Hopkins Hospital between 2000-2019. During this period, a total of 644 cases were diagnosed as SFM. Of these, 55 cases of “Suspicious for non-papillary thyroid carcinoma (SNPTC) were identified. These 55 cases were then compared with 65 random cases of “Suspicious for Papillary Thyroid Carcinomas (SPTC) diagnoses as a control group. Results The Suspicious for Non-Papillary Thyroid Carcinoma (SNPTC) subgroup consisted of 28 cases of “Suspicious for Medullary Thyroid Carcinoma (SMTC)” (50.91%), 4 cases of Suspicious for Metastasis (SMET) (7.27%), 3 cases of “Suspicious for Malignant Lymphoma (SML) (5.45%), 2 cases of ‘Suspicious for Poorly-Differentiated Thyroid Carcinoma (SPDC) (3.64%), and 18 cases of “Suspicious for Malignancy, Not Otherwise Specified (SNOS) (32.73%). When compared to the “Suspicious for Papillary Thyroid Carcinoma (SPTC)”, SNPTC patients’ average age was older (p=0.004). Ancillary studies assisted in diagnosing SNPTC more so than SPTC (p Conclusions SNPTC was rarely diagnosed when compared to SPTC. SMTC was the most commonly diagnosed SNPTC subgroup, followed by SNOS. The ROM of SNPTC was slightly lower than that of SPTC. Ancillary studies and previous clinical history, in addition to cytomorphology, was helpful when rendering the diagnosis of SNPTC.