CD30-Positive NLPHL mimicking CHL

Lessons From the Friday Unknowns

Histologic sections show lymph node involved by lymphoma with a nodular and focally diffuse patterns.

The lymphoma is composed of atypical large lymphocytes, some with Hodgkin-like appearance and others more consistent with LP cells. The background is predominantly composed of small lymphocytes and histiocytes. Neutrophils are very rarely seen while eosinophils are virtually absent.

Immunohistochemical studies show that the tumor cells are positive for CD20 (strong and uniform), PAX-5, OCT2 (strong), are CD30 (variable intensity and subset) and are negative for IgD, EMA, CD3 and CD15. CD45 seems to be positive in a subset of the tumor cells, while negative in some cells. CD21 highlights preserved networks of follicular dendritic cells inside in most of the neoplastic nodules. EBER is difficult to interpret and could be positive in a subset off the tumor cells.

In summary, the overall features are consistent with NLPHL. The neoplasm has a variety of patterns including patterns C and focally E (diffuse).