Primary Thyroid Lymphoma: Clinical Factors Predicting the Possibility of Diffuse Large B-Cell Lymphoma.

Aims: Among primary thyroid lymphomas (PTLs), diffuse large B-cell lymphoma (DLBCL) has a poorer prognosis than other indolent lymphomas such as mucosa-associated lymphoid tissue (MALT) or follicular lymphoma (FL). However, the clinical differences between DLBCL and indolent lymphoma remain unclear. Therefore, this retrospective study on PTL was aimed at investigating the clinical differences between DLBCL and indolent lymphomas and identifying the factors differentiating DLBCL from indolent lymphomas. Materials and Methods: Medical records of 28 patients diagnosed with PTL and treated at our institution between 2005 and 2022 were retrospectively analyzed. Data on the following clinical variables were extracted: sex, age, symptoms (pain and dysphagia), ultrasonographic appearance patterns, the presence of airway stenosis on computed tomography and laryngeal endoscopy, blood test results, disease stage, and pathological diagnosis. Results: In all, 13 patients were histologically diagnosed with DLBCL, 12 with MALT lymphoma, and 3 with FL. Significant differences in disease-specific survival rates were evident between the DLBCL and indolent lymphoma groups (68.2 vs 100%, P = .043). High lactate dehydrogenase levels (>230 U/mL) and airway stenosis were observed only in patients with DLBCL. Multivariate analysis identified that the presence of a linear echoic strand pattern and the absence of an echoic nodular pattern on ultrasound were independently associated with DLBCL ( P = .0497 and .012, respectively). Conclusion: DLBCL can cause airway stenosis. The linear echogenic strand pattern and the absence of a nodular pattern should be recognized as predictive factors of DLBCL.