Ultrasound characteristics of thyroid nodules diagnosed as follicular neoplasms by fine-needle aspiration cytology

Summary

Cytopathological evaluation has been proven useful in the diagnostic work-up of “cold” nodules. The cytological diagnosis of follicular neoplasm usually requires histology to exclude malignancy. The objective of this prospective study was to test the hypothesis that ultrasound examinations show distinct characteristics in a subgroup of nodules which may attest the benign nature of a follicular neoplasm. Patients, methods: 56 patients (45 women, 11 men) were included in the study. All patients had a “cold” nodule which was diagnosed as follicular neoplasm. Consecutive histology revealed follicular adenomas (FTAs) (n = 44), follicular carcinomas (FTCs) (n = 7) and papillary carcinomas (PTCs) (n = 5), including follicular variant papillary carcinomas (fv PTCs) (n = 4). Ultrasound examinations were performed preoperatively. The ultrasound examinations were evaluated with respect to seven characteristics. Results: In 21 % of patients a follicular neoplasm was associated with a malignant and in 79 % of patients with a benign tumor as compared with histology. The ultrasound characteristics size 2 ml, round shape and homogeneous structure revealed significant differences for FTAs, FTCs and PTCs with p < 0.001, p = 0.003 and p = 0.027, resp. With respect to the benign nature of a follicular neoplasm maximum values for sensitivity and specificity were 0.75 and 0.83. Multivariate discriminant analysis revealed that ultrasound criteria were suitable to discriminate between benign vs. malignant nodules and among FTAs, FTCs and PTCs with correlation coefficients of r = 0.53 and r = 0.74, resp. Conclusions: in selected patients with higher operative risks and cytological diagnosis of follicular neoplasm ultrasound parameters may be helpful to assume a benign nature of the neoplasm and thus avoid the necessity of a histological work-up.

Zusammenfassung

Bei der Abklärung „kalter“ Schilddrüsenknoten kommt der Zytopathologie ein hoher Stellenwert zu. Die zytologische Diagnose einer follikulären Neoplasie erfordert in der Regel eine histologische Abklärung, um eine maligne Dignität auszuschließen. Das Ziel dieser prospektiven Studie war die Prüfung der Hypothese, dass eine Subgruppe von Schilddrüsenknoten charakteristische Ultraschallmerkmale aufweisen, die für eine benigne Dignität der follikulären Neoplasie sprechen. Patienten, Methoden: 56 Patienten (45 Frauen, 11 Männer) nahmen an der Studie teil. Alle Patienten hatten einen „kalten“ Schilddrüsenknoten, bei dem zytologisch die Diagnose einer follikulären Neoplasie gestellt worden war. Die histologische Abklärung ergab follikuläre Adenome (FTAs) (n = 44), follikuläre Karzinome (FTCs) (n = 7) und papilläre Karzinome (FTCs) (n = 5), einschließlich follikulärer Varianten der papillären Karzinome (fv PTCs) (n = 4). Präoperativ wurden Ultraschall-Untersuchungen der Schilddrüse durchgeführt und im Hinblick auf sieben Charakteristika ausgewertet. Ergebnisse: Aufgrund der Histologie handelte es sich bei 21% der Patienten mit einer follikulären Neoplasie um eine maligne und in 79% um eine benigne Dignität. Die Ultraschall-Charakteristika „Größe“ 2 ml, runde Form und homogene Struktur wiesen bei FTAs, FTCs und

Keywords

Ultrasound - fine-needle aspiration biopsy - cyto logy - follicular neoplasms - follicular adenomas - follicular carcinomas

Schlüsselwörter

Ultraschall - Feinnadelaspirationsbiopsie - Zyto logie - follikuläre Neoplasien - follikuläre Adenome - follikuläre Karzinome

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