This is a 28-year-old male with enlarged right axillary lymph node that was biopsied. A pathology opinion is requested at this time due to concern for Hodgkin lymphoma.

The findings below are characteristic for progressive transformation of germinal centers which is often associated with adenopathy and nodal enlargement. A proportion of patients have autoimmune conditions.

Learning points:

1. Large expansile follicles with ingrowth of mantle zone cells into these follicles is a typical morphology in this condition.
2. IgD is a useful mantle zone stain that highlights these cells encroaching into the follicles.
3. Scattered large OCT-2+/PAX5+ centroblasts or immunoblasts may be mistaken for cells of nodular lymphocyte predominant Hodgkin lymphoma and this remains a pitfall.