What is the hallmark cell in Hodgkin lymphoma and a common clinical feature?

• A. Reed-Sternberg cells; painless lymphadenopathy often with mediastinal involvement
• B. Auer rods; bone pain
• C. Smudge cells; lymphocytosis
• D. Dendritic cells; skin lesions

Answer: (A)

Reed-Sternberg cells are the large, abnormal B cells with two nuclei and prominent nucleoli, giving an owl-eye appearance. Their presence—amid a mixed inflammatory background—is the defining feature of Hodgkin lymphoma. Clinically, this disease most often presents as painless lymphadenopathy, commonly in the neck, with mediastinal involvement frequently seen on imaging.

Other options point to different diseases: Auer rods are linked to acute myeloid leukemia; smudge cells are associated with chronic lymphocytic leukemia; dendritic cells with skin lesions relate to dendritic cell histiocytosis.