Name : Mohammad
Affiliation : Sepehr imaging center,Rasht,Iran
Academic Degree: Radiologyist
Resident : Ramin Pourghorban
Gender : Female
Age : 54
Head & Neck Imaging
54 year-old female with neck mass
Imaging Procedures and Findings
Axial contrast-enhanced CT shows a relatively homogeneous, noncalcified mass in the left lobe of the thyroid that infiltrates the adjacent soft tissues. Upper mediastinal involvement and tracheal narrowing are also evident. Biopsy showed round cell tumor morphologically consistent with malignant lymphoma and immunohistochemical staining results was as below: CD45 and CD20: positive, cytokeratin (AE1/AE3): negative, CD10: negative, Ki67 index>90%, CD5 and CD45RO: some small lymphocytee in the background are positive The above findings are consistent with diffuse large B-cell lymphoma.
Primary thyroid lymphoma is a rare disease that can be confused with anaplastic thyroid carcinoma radiographically and, in the past, even pathologically, although new immunohistochemical stains make the pathologic diagnosis easier. Most thyroid lymphomas are of B-cell origin, but there appears to be two distinct clinical and prognostic subtypes of these rare tumors. The more indolent lymphomas are the subgroup of mucosa-associated lymphoid tissue (MALT) lymphomas, comprising 6% to 27% of thyroid lymphomas. Localized disease in this subgroup responds well to total thyroidectomy or radiation, with a complete response rate of more than 90%. Diffuse large B-cell lymphoma is the more common subtype, representing 70% of thyroid lymphomas, and in some cases may arise from MALT lymphomas. This subtype appears to have the most aggressive clinical course, with almost 60% of these tumors diagnosed with disseminated disease. On imaging, primary thyroid NHL most commonly presents as a solitary, rapidly enlarging mass mimicking anaplastic thyroid carcinoma or other aggressive carcinoma. On cross-sectional imaging, thyroid lymphoma tends to be more homogeneous than thyroid carcinoma, and calcification or cystic degeneration or necrosis is rare, distinguishing it from goiter. Although tracheal invasion is not uncommon in thyroid carcinomas, lymphoma is rarely associated with tracheal invasion, although significant narrowing of the airway can occur.
diffuse large B-cell lymphoma of thyroid
Aiken AH, Glastonbury C. Imaging Hodgkin and Non-Hodgkin Lymphoma in the Head and Neck. Radiol Clin North Am 2008;46: 363-378.