What are the two major categories of lymphoma and a hallmark difference between them?

• A. Hodgkin lymphoma with Reed-Sternberg cells and contiguous spread; non-Hodgkin lymphoma with diverse B/T/NK-cell lymphomas and noncontiguous spread.
• B. Hodgkin lymphoma has noncontiguous spread; non-Hodgkin lymphoma has contiguous spread.
• C. Both are identical except for age distribution.
• D. Hodgkin lymphoma and non-Hodgkin lymphoma differ only in treatment response.

Answer: (A)

The main concept here is how Hodgkin lymphoma differs from non-Hodgkin lymphoma in what they look like under the microscope and how they typically spread. Hodgkin lymphoma is defined by the presence of Reed-Sternberg cells, those large, often binucleated B cells that give the disease its characteristic appearance. This type tends to spread in a contiguous, stepwise fashion from one lymph node region to the next, rather than jumping to distant sites early.

Non-Hodgkin lymphoma, by contrast, includes a broad group of lymphoid cancers arising from B, T, or NK cells. The histology is diverse, with many subtypes, and the disease often spreads noncontiguously, involving multiple nodal regions and extranodal sites, sometimes widespread at diagnosis.

So the best description captures both the Reed-Sternberg hallmark of Hodgkin lymphoma and its contiguous spread, versus the diverse B/T/NK-cell lineage and noncontiguous spread seen in non-Hodgkin lymphoma. The other statements don’t fit this fundamental distinction.