Primary mediastinal large B-cell lymphoma must be differentiated from other diseases that cause swollen face, superior vena cava syndrome, and fever, night sweats and weight loss such as hodgkin’s lymphoma, thymoma, and other non hodgkin’s lymphomas.

• Primary mediastinal large B-cell lymphoma must be differentiated from other diseases that cause swollen face, superior vena cava syndrome, and fever, night sweats and weight loss such as hodgkin’s lymphoma, thymoma, and other non hodgkin’s lymphomas.

• The differentiation is determined on the basis of biopsy findings and immunophenotype, which are as follows:

• Thymoma
  • Thymic epithelial cells stain for epithelial markers such as keratin and epithelial membrane antigen.^[1]
• Hodgkin’s lymphoma^[2]
  • Reed-Sternberg cells typically express CD15 and CD30
• Thymic carcinoma
  • The lymphocytes have phenotype of mature T cells (CD1a-, CD3+, and CD4+ or CD8+.^[3]
• Acute myeloid Leukemia
  • Myeloblasts immature cells with large nuclei, prominent nucleoli, and a variable amount of pale blue cytoplasm with auer rods^[4]
• Diffuse large B-cell lymphoma
  • Involvement of bone marrow or distant lymph nodes is indicative of systemic DLBCL with secondary mediastinal involvement.
• Mediastinal germ cell tumor^[5]
  • Germ cell tumor markers such as beta-human chorionic gonadotropin [hCG] and alpha fetoprotein are positive.