Legend: H&E section (a: 4X) and (b: 10X) showing schwannoma, with interspersed small lymphoid aggregates and a plasma cell infiltrate on the right. (c) S-100 showing diffuse and strong, cytoplasmic, and nuclear positivity in the schwannoma component on the left (10x). (d) CD138 immunostain (10x) showing plasma cells infiltrating into the schwannoma. In situ hybridization studies for kappa (e) and lambda (f) light chains (10x) show that the plasma cells are kappa-restricted. (g) CD3 (10x) highlights T cells scattered interstitially and within the lymphoid aggregates. (h) CD20 (10X) highlights few scattered B cells. (i) Ki-67 (10x) shows very low proliferative activity.