Fig. 12. Mantle zone lymphoma. A. A monomorphous diffuse infiltrate of medium-sized cells (hematoxylin and eosin, × 10). B. Lymphocytes in mantle zone lymphoma have irregular nuclei, inconspicuous nucleoli, and scant cytoplasm (hematoxylin and eosin, × 60). (Courtesy of Dr. A. Mowat)