The ultrastructural cellular inclusions referred to as ribosome-lamella complexes were observed in the neoplastic cell population of 4 patients with three types of hematopoietic malignancy, monoblastic leukemia. Waldenstrom's macroglobulinemia, and chronic lymphatic leukemia. The ultrastructural characteristics of the inclusions were similar in the 4 cases. The percentage of cells affected ranged from approximately 90% in 1 patient with monoblastic leukemia to approximately 10% in a patient with Waldenstrom's macroglobulinemia. The complexes appeared to originate from the rough endoplasmic reticulum. Observations suggested a developmental sequence beginning with aggregate strands of rough endoplasmic reticulum, subsequent alignment of the strands of rough endoplasmic reticulum in a concentric configuration, followed by maturation to fully developed ribosome-lamella complexes. Although the ribosome-lamella complex has been found in the neoplastic cells of several patients with leukemic reticuloendotheliosis ("hairy cell leukemia"), its occurrence in these three different hematopoietic disorders indicates a lack of diagnostic specificity of this structure.
Acute Disease Cytoplasm