Morphological features and immunostaining for MAL of PMBLs and peripheral DLBLs. (A) PMBL of centroblastic subtype with a clear-cell component (case no. 10). (B) Case no. 10 stained for the MAL protein showing surface membrane and granular cytoplasmic immunoreactivity with accentuation in the Golgi area of neoplastic cells. (C) PMBL of centroblastic polymorphic subtype with a anaplastic large-cell component (case no. 2). (D) Staining for MAL of case no. 2 showing membrane and striking paranuclear dot-like positivity in neoplastic cells (inset). (E) Peripheral DLBL of centroblastic multilobated subtype (case no. 17). (F) Staining for MAL of case no. 17 showing that the tumor cells lack expression of the MAL protein. Positive internal control are present, represented by small lymphoid cells, consistent with reactive T cells. (A, C, and E, hematoxylin-eosin stain; B, D, and F, immunohistochemical staining of paraffin section with the anti-MAL antibody, APAAP method.)