Morphologic and phenotypic features of the lymphomas described in this report. (A and B) Characteristic sinusoidal growth pattern and cellular morphology (Giemsa stain). (C through F ) Immunostaining reactions. EMA is strongly expressed (C) but CD30 is absent (D). Neoplastic cells express IgA (E) but in a section stained for IgM (F ) only plasma cells are stained. (Immunoperoxidase staining with nuclear counterstain.)