Ultrasound scanning in diagnosing primary thyroid lymphoma.

Objective: This study aimed to summarize the clinical manifestations and ultrasound characteristics of primary thyroid lymphoma (PTL) and explore the key aspects in the process of diagnosing PTL.

Methods: We conducted a retrospective analysis of the clinical and ultrasound features of 11 patients with PTL who were admitted to Shandong Provincial Third Hospital, China, between May 2009 and August 2023. The pathology was confirmed in all cases through an ultrasound-guided core needle biopsy or surgical resection.

Results: The mean age of the 11 patients was 64.45±9.85 years. In six patients, the main clinical manifestation was a palpable mass in the neck, five of whom had a significant increase in the size of the mass within 3 months to 2 years. Eleven patients had coexisting Hashimoto's thyroiditis (HT). Three patients were diagnosed as having diffuse-type PTL, wherein the ultrasound showed enlargement of the affected thyroid gland with diffusely uneven hypoechoic parenchyma. In 7 patients with nodular type PTL and 1 case of mixed type PTL, the ultrasonographic features of the nodular lesions were of irregular morphology and yet had distinct borders, and only 1 case had gross calcification. There were 7 cases of hypoechoic lesions (7/11 cases, 63.6%), 9 cases where the lesions had linear echo chains (9/11 cases, 81.8%), and 10 cases (90.9%) where there was echogenic enhancement posterior to the lesion.

Conclusion: In elderly patients with HT, the thyroid volume increases significantly in a short period of time and symptoms associated with compression in the neck region appear. The ultrasound characteristics were extremely hypoechoic lesions in the thyroid parenchyma, with more linear echo chains visible inside, accompanied by posterior echo enhancement. When encountering such presentations, physicians must consider the possibility of PTL. Performing a core needle biopsy in cases that raise suspicion can reduce the incidence of misdiagnosis.