To summarize the multimodal ultrasonographic characteristics primary thyroid lymphoma (PTLs), and to discuss the diagnosis and differential diagnosis of PTLs.

Multimodal ultrasonographic charactericsits of six cases of PTLs were analyzed retrospectively. All of the patients were examined by the conventional two-dimensional ultrasound (2DUS), color Doppler flow imaging (CDFI), contrast-enhanced ultrasound (CEUS), three-dimensional ultrasound (3DUS) reconstruction and elastography imaging (EI) from October 2011 to February 2016 in Changzheng Hospital, affiliated to Secondary Military Medical University. All diagnoses were confirmed by ultrasound-guided percutaneous biopsy.

(1) 2DUS: six cases of PTLs without capsule were observed as diffusely enlargement type (two cases), unilateral nodular type (one case, on left lobe),and bilateral multiple nodular type (the other three cases). The margin of the multiple nodules were not clear, and some nodules were fused with each other.There were four cases of heterogeneous (extremely) hypoechogenicity and two cases of mixed echogenicity, All of the lesions were characterized by various striped and reticular hyperechogenicity interiorly on ultrasonograms, and only one case showed slightly posterior enhancement. Except one case, multiple cervical lymphnodes hyperplasia were identified on neck regionⅡ-Ⅴin five cases. (2) CDFI and CEUS: CDFI showed abundant blood flow signals in the PTLs nodules peripherally and internally. The striped blood flow was observed in the lesions, and spectrum showed as artery and veins. The plentiful vascular tree was also found in the enlarged lymphnodes. By using high frequency CEUS, six cases of the PTLs demonstrated diffuse and heterogeneous enhancement significantly, including little necrosis area without prominent contrast agent filling in two cases. (3) 3DUS reconstruction: Various striped and reticular hyperechoic features were found on the surface of six cases of PTL nodules. (4) EI: All lesions were soft in six cases. The ratio of elastic strain rate was 1.28-1.96, average (1.82±0.29).

The ultrasonographic features of PTLs are of certain characteristics, and multiple modes of ultrasound examination can help to grasp the comprehensive imaging informations of PTLs, which should be encouraged positively to facilitate the early detection, early diagnosis and early treatment for PTLs.