Primary Thyroid Diffuse Large B-Cell Lymphoma Presenting As A Rapidly Progressive Compressive Goitre: A Case Report.

Abstract

Background:
Primary thyroid lymphoma (PTL) is a rare extranodal lymphoma that typically arises in a background of chronic autoimmune thyroiditis and often presents as a rapidly enlarging goitre with compressive symptoms, closely mimicking anaplastic or other aggressive thyroid malignancies. Diffuse large Bcell lymphoma (DLBCL) is the most common high-grade PTL subtype and may progress abruptly, making prompt tissue diagnosis and immunophenotyping essential to guide lymphoma-directed therapy.
Case report:
A 52-year-old woman presented with a rapidly enlarging anterior neck mass associated with fever, dysphagia, and respiratory distress. Examination revealed a solid thyroid mass measuring approximately 10 × 6 × 5 cm with irregular surface and diffuse cervical lymphadenopathy. Due to progressive pressure symptoms, she underwent isthmulobectomy at a rural hospital. Initial histopathology showed lymphocytic thyroiditis with atypical lymphoid proliferation suspicious for intermediate-to-large cell non-Hodgkin lymphoma. Postoperative ultrasonography demonstrated multiple bilateral cervical lymphadenopathies (levels III–IV) and right thyroid fossa lymphadenopathy, with spongiform lesions in the contralateral lobe. After referral, immunohistochemistry confirmed DLBCL with CD20 positivity, CD3 negativity, and a high proliferative index (Ki-67: 95%). Staging with thoracic computed tomography revealed subcarinal lymphadenopathy without pulmonary metastases; disease was classified as stage IIE (extranodal organ with regional nodes). The patient was treated with immunochemotherapy (R-CHOP) and remained clinically well during the third cycle.
Conclusion:
PTL should be strongly considered in patients—particularly women with thyroiditis—who develop a rapidly progressive goitre with compressive symptoms and cervical lymphadenopathy. Adequate tissue sampling with immunohistochemistry is critical for distinguishing DLBCL from thyroid carcinoma and for enabling timely initiation of rituximab-based chemotherapy, which can achieve favorable early outcomes and help avoid unnecessary extensive surgery.