Citation, DOI & article data
Giraffe pattern (also known as the pseudonodular appearance) is a distinctive ultrasound appearance characteristic of Hashimoto thyroiditis. Bonavita originally described a thyroid gland with multiple echogenic nodules, separated from one another by bands of hypoechogenicity, reminiscent of a giraffe hide 1. Studies have shown that this pattern is always benign.
The reverse pattern, multiple hypoechoic pseudonodules with ill-defined margins surrounded by echogenic areas of thyroid parenchyma or fibrosis, is also characteristic of Hashimoto thyroiditis and more similar to giraffe hide which consists of dark areas surrounded by bright lines.
The pattern on vascular Doppler is also helpful to differentiate pseudonodules from true thyroid nodules, the hypoechoic areas are avascular and intervening parenchyma shows vascularity.
- 1. Bonavita JA, Mayo J, Babb J, Bennett G, Oweity T, Macari M, Yee J. Pattern recognition of benign nodules at ultrasound of the thyroid: which nodules can be left alone?. (2009) AJR. American journal of roentgenology. 193 (1): 207-13. doi:10.2214/AJR.08.1820 - Pubmed
- 2. Virmani V, Hammond I. Sonographic patterns of benign thyroid nodules: verification at our institution. (2011) AJR. American journal of roentgenology. 196 (4): 891-5. doi:10.2214/AJR.10.5363 - Pubmed
- 3. Ceylan I, Ceylan YS, Ceylan BF, Ceylan SM. Roles of ultrasound and power Doppler ultrasound for diagnosis of Hashimoto thyroiditis in anti-thyroid marker-positive euthyroid subjects. (2014) Quantitative Imaging in Medicine and Surgery. 4 (4): 232-238. doi:10.3978/j.issn.2223-4292.2014.07.13 - Pubmed
- 4. Sonographic Patterns of Benign Thyroid Nodules. (2012) American Journal of Roentgenology. 198 (1): W102-3. doi:10.2214/AJR.11.7737 - Pubmed
- 5. Yildirim D, Nodule or pseudonodule? Differentiation in Hashimoto's thyroiditis with sonoelastography. (2020) The Journal of international medical research. doi:10.1177/147323001103900636 - Pubmed