An 85-year-old woman presents with increasing fatigue and weight loss over the past 3 months. A CT scan of the abdomen reveals a 4-cm retroperitoneal mass. Fine-needle aspiration reveals numerous, large, noncleaved dissociated cells. By flow cytometry, the cells are positive for CD10, CD19, CD20, IgM, and lambda light chains. Which of the following is the appropriate diagnosis?
Acute myelogenous leukemia
Adult T-cell lymphoma/leukemia
Answer : C B-cell lymphoma
Lymphomas are malignant proliferation of lymphocytes or lymphoblasts. The World Health Organization classification distinguishes between Hodgkin lymphoma and B-cell and T-cell lymphomas (non- Hodgkin lymphomas).
B-cell lymphomas are characterized by their expression of cell surface immunoglobulin heavy and light chains and other cell surface CD antigens (e.g., CD20).
The other choices do not express cell surface immunoglobulin
heavy or light chains.