Lessons From the Friday Unknowns
Immunoperoxidase stained sections for CD20, PAX 5, CD3, CD5, CD10, CD138, kappa, lambda and CD21 were submitted for review.
CD138 positive plasma cells are mainly within the sinusoids of the lymph node. Kappa and lambda immunostains show a polytypic pattern of positivity of plasma cells. The other immunostains show results compatible with a diagnosis of florid reactive follicular hyperplasia with follicular lysis and prominent monocytoid B-cell hyperplasia with neutrophils in a deep right axillary lymph node.