Welcome to Managing Hodgkin Lymphoma. My name is Andy Evens, and I am Professor of Medicine and Chief of the Division of Hematology/Oncology and Director of the Tufts Cancer Center at Tufts Medical Center in Boston, Massachusetts. I am frequency asked what the relative roles of immunohistochemical studies are versus flow cytometry results in the accurate diagnosis and assessment of patients with Hodgkin lymphoma. The quick answer is that both are important. As such, it is generally important to have a good relationship with your pathologist.

Sometimes these diagnoses can be hard to make in terms of just the general diagnosis of classical Hodgkin lymphoma. As you know, only 1% or less of the cells in a biopsy specimen are actually the Reed-Sternberg or Hodgkin and Reed‑Sternberg (HRS) malignant cells, the rest is microenvironment. So especially now, we are seeing an increase in the number of core biopsies; because it can be difficult to make a diagnosis, that is always the first step. Excisional or incisional lymph node biopsies are still recommended to fully understand the diagnosis and the spectrum; it is complementary. Immunohistochemical stains are still done routinely.

Flow cytometry can still be helpful for the diagnosis of classical Hodgkin lymphoma, as well as for differentiating between some of the more uncommon subtypes. These subgroups include gray-zone lymphoma, which contains some parts and similarities to classical Hodgkin lymphoma, as well as diffuse large B-cell lymphoma, and then another entity known as nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL).

So, again, in summary, I would say both immunohistochemistry and flow cytometry are important in establishing the diagnosis and differentiating between the different subtypes. Thank you for viewing this activity.

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