ALK+ ALCL with EBER Positive Cells

Lessons From the Friday Unknowns

Histologic evaluation demonstrates alteration of nodal architecture by an infiltrate of large neoplastic lymphoid cells with anaplastic features exhibiting sinusoidal involvement.

By immunohistochemistry, the neoplastic cells are positive for CD30 and ALK (nuclear and cytoplasmic), and they are negative for CD2, CD3, CD5, CD7, CD20, PAX,5, pancytokeratin and panmelanoma cocktail.

CD30

CD30 stain demonstrating sinusoidal distribution of the lymphoma cells

The neoplastic cells are positive for CD30 and ALK (nuclear and cytoplasmic), and they are negative for CD2, CD3, CD5, CD7, CD20, PAX,5, pancytokeratin and panmelanoma cocktail. Background lymphocytes consist predominantly of T-cell with few small B-cells.

The neoplastic cells are positive for ALK-1 expression

In situ hybridization for EBV (EBER) demonstrates few positive calls of various sizes, including some large cells, whereas EBV-LMP1 immunohistochemistry stain is positive in rare small lymphocytes.

EBER stain positivity in few background cells

The findings in this sample are diagnostic of ALK-positive anaplastic large cell lymphoma. The clinical significance of EBV detection in this context is not clear but might reflect immune system suppression/dysregulation related to the underlying lymphoma.

Links to digital slides: https://bit.ly/2WPswfd | Slides labeled case 5

Further read:

Epstein-Barr virus association and ALK gene expression in anaplastic large-cell lymphoma - PubMed