A 55-year-old man felt a lump near his shoulder 1 week ago. On physical examination, there is an enlarged, nontender, supraclavicular lymph node and enlargement of the Waldeyer ring of oropharyngeal lymphoid tissue. There is no hepato- splenomegaly. CBC is normal except for findings of mild anemia. A lymph node biopsy specimen shows replacement by a monomorphous population of lymphoid cells that are twice the size of normal lymphocytes, with enlarged nuclei and prominent nucleoli. Immunohistochemical staining and flow cytometry of the node indicates that most lymphoid cells are CD19+, CD10+, CD3-, CD15-, and terminal deoxynucleotidyl transferase negative (TdT-). A BCL6 gene mutation is present. Which of the following is the most likely diagnosis?
Correct Answer: Diffuse large B-cell lymphoma
Description: Diffuse large B-cell lymphoma occurs in older individuals and frequently manifests as localized disease with extranodal involvement, particularly of the Waldeyer ring. A third of cases have BCL6 rearrangements or mutations. The staining pattern indicates a B-cell proliferation (CD19+, CD10+). T-cell (CD3) and monocytic (CD15) markers are absent. TdT can be expressed in B lineage cells at an earlier stage of maturation. Lymphoblastic lymphoma is a T-cell neoplasm that occurs typically in the mediastinum of children. In chronic lymphadenitis, the lymph node has many cell types-macrophages, lymphocytes, and plasma cells. A monomorphous infiltrate is typical of non-Hodgkin lymphomas. Reed-Sternberg cells characterize Hodgkin lymphoma. Small lymphocytic lymphoma also is a B-cell neoplasm, but it manifests with widespread lymphadenopathy, liver and spleen enlargement, and lymphocytosis.
Category:
Pathology
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