Hodgkin lymphoma
USMLE Step 1Difficulty: mediumLast updated:
A 24-year-old woman is evaluated for a painless, rubbery left supraclavicular lymph node that has enlarged over 2 months. She reports drenching night sweats and a 6-kg weight loss. Chest x-ray shows a mediastinal mass. Excisional biopsy of the node shows bands of collagen dividing the node into nodules. The nodules contain scattered large binucleated cells with prominent nucleoli in a background of small lymphocytes, eosinophils, histiocytes, and plasma cells.
Immunohistochemical staining of the large cells is most likely to show strong positivity for which of the following?
Answer and explanation
Correct answer: B. CD30
A young adult with a mediastinal mass, B symptoms, and a nodular, fibrotic node containing large binucleated cells in a mixed inflammatory background has classic Hodgkin lymphoma (nodular sclerosis subtype). The source review states that Hodgkin and Reed-Sternberg (HRS) cells are universally positive for CD30 and variably positive for CD15, and that CD30 is a defining marker of classic Hodgkin lymphoma. The same review notes that HRS cells are negative or only weakly positive for CD20, unlike the LP cells of nodular lymphocyte-predominant Hodgkin lymphoma. CD30 is also the target of brentuximab vedotin, an antibody–drug conjugate used in relapsed or refractory classic Hodgkin lymphoma. The Merck Manual describes the biopsy picture: Reed-Sternberg cells in a heterogeneous infiltrate of histiocytes, lymphocytes, monocytes, plasma cells, and eosinophils.
Each option explained
- A. CD5Incorrect. CD5 is expressed by T cells and by CLL/SLL and mantle cell lymphoma, not by HRS cells.
- B. CD30Correct. HRS cells of classic Hodgkin lymphoma are universally CD30-positive (and variably CD15-positive).
- C. CD34Incorrect. CD34 marks immature hematopoietic precursors (e.g., blasts in acute leukemia).
- D. MyeloperoxidaseIncorrect. Myeloperoxidase is a myeloid marker, not expressed by Reed-Sternberg cells.
- E. CD3Incorrect. CD3 is a T-cell marker; HRS cells are derived from B cells, and the small background T cells are reactive.
Key point
Reed-Sternberg cells of classic Hodgkin lymphoma are CD30-positive and variably CD15-positive.
From the source
“HRS cells are universally positive for CD30 ... and variably positive for CD15.”