Primary Mucosa-Associated Lymphoid Tissue Lymphoma of Thyroid with the Serial Ultrasound Findings

Figure 4

(a) Microscopic finding shows the extranodal marginal zone lymphoma of MALT in a background of Hashimoto’s thyroiditis (H&E stain, ×20). (b) Microscopic finding of the thyroid mass shows marked lymphocytic infiltration and a few degenerated follicles (H&E stain, ×200). (c) Immunohistochemical findings disclose diffuse positive staining for CD20 (immunohistochemistry, ×200). (d) Immunostaining for cytokeratin highlights lymphoepithelial lesions (immunohistochemistry, ×200).

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