Are thyroid nodules with spongiform morphology always benign

OBJECTIVE: Fine needle aspiration (FNA) biopsy for evaluation of spongiform nodules ≥20 mm or observation without FNA was recommended by American Thyroid Association. However, this was a weak recommendation supported by moderate quality evidence. We aimed to assess malignancy risk in spongiform nodules. METHODS: From January 2015 to June 2016, an experienced endocrinologist performed B-mode greyscale ultrasonography and observed 96 spongiform nodules among 3748 ultrasound procedures. Power Doppler ultrasonography and ultrasound-guided FNA were performed to 96 spongiform nodules. Both colour elastography and strain ratio measurements of dominantly solid areas were performed. RESULTS: All spongiform nodules had benign cytology. Fifty-two (54.2%) nodules were ≥20 mm and 44 (45.8%) were smaller than 20 mm in maximum diameter. Presence of ultrasonography features related to malignancy was rare; 2% (n = 2) microcalcification, 9.4% (n = 9) taller than wide shape and 2% (n = 2) marked central blood flow were noted. None of the nodules had two or more suspicious features. Ultrasound elastography findings revealed that dominantly solid components of nodules were usually soft as 66.7% had an elasticity score 1 according to colour scale and mean strain ratio was 1.39 ± 0.99. CONCLUSIONS: Follow-up with ultrasonography seems to be an efficacious method even for spongiform nodules larger than 2 cm. Determination of soft appearance according to colour map on ultrasound elastography and low strain ratio values of dominantly solid areas may be useful to avoid unnecessary biopsies.