ABSTRACT
A case of CD30-positive microvillous lymphoma (MVL) in an 87-year-old man who was encountered generalised lymphadenopathy is presented. Histopathologically, the tumour showed a morphological mimic of anaplastic large cell lymphoma (ALCL) with sinusoidal growth pattern. Immunohistochemically (IHC), the tumour cells were CD30(+), CD20(+), CD45(+), BCL-2(+), BCL-6(+), MUM1(+), Ki-67(+), CD45RO(-), CD3(-), CD10(-), CD15(-), CD56(-), EMA(-), TIA-1(-) and ALK(-). Flow cytometry confirmed the IHC. In situ hybridisation for Epstein-Barr virus RNA was negative. Electron microscopically, the tumour cells were similar to large transformed lymphocytes and had circumferentially profuse microvillous projections resembling those of epithelial mesothelioma cells. In conclusion, CD30-positive MVLs are indistinguishable from ALCLs that have ultrastructural microvillous projections by morphology alone. However, the lack of EMA, TIA-1 and ALK expression in this MVL case facilitated a definite distinction from ALCLs. The results of a panel of three markers (CD10(-), Bcl-6(+) and MUM1(+)) suggested that the present case of CD30-positive MVLs has an activated non-germinal centre B-cell origin.
Subject(s)
Ki-1 Antigen/analysis , Lymphoma, Large B-Cell, Diffuse/ultrastructure , Aged, 80 and over , Biomarkers, Tumor/analysis , Diagnosis, Differential , Humans , Lymphoma, Large B-Cell, Diffuse/diagnosis , Lymphoma, Large B-Cell, Diffuse/metabolism , Lymphoma, Large-Cell, Anaplastic/diagnosis , Male , Microscopy, Electron , Microvilli/ultrastructureABSTRACT
In the attempt to develop a pre-embedding immunoelectron microscopic method with improved ultrastructral morphology, we examined an antigen retrieval (AR) method using citraconic anhydride, and compared the effects of glutaraldehyde fixation with routine paraformaldehyde fixation in the pre-embedding immunoelectron microscopic method with reference to the localization of surfactant-associated pro-protein C (proSP-C) in the lung. The glutaraldehyde-fixed tissues were immunostained after AR in 0.05% citraconic anhydride solution, pH 7.4, at 98 degrees C for 60 min. In routine pre-embedding immunoelectron microscopic method using paraformaldehyde fixation, proSP-C positive products were distributed sporadically in the type II alveolar epithelial cells. In glutaraldehyde-fixed tissues without the AR method, proSP-C products were not detected, however after AR in citraconic anhydride proSP-C positive products were distributed specifically, in rough endoplasmic reticulum membranes, Golgi complex membranes, multivesicular bodies and osmiophilic lamellar bodies. The positive proSP-C products also showed lattice-like structures in the alveoli. Thus, the present AR method provides successful pre-embedding immunoelectron microscopy of glutaraldehyde-fixed tissues.
Subject(s)
Citraconic Anhydrides , Epithelial Cells/metabolism , Peptides/metabolism , Pulmonary Alveoli/metabolism , Animals , Epithelial Cells/ultrastructure , Female , Fixatives , Formaldehyde , Glutaral , Microscopy, Immunoelectron , Polymers , Pulmonary Alveoli/ultrastructure , Rats , Rats, Wistar , Tissue FixationABSTRACT
A new electron microscopic method is described in which superior staining of basement membranes, collagen fibers and glycogen particles in various tissues was achieved. This method uses a gelatin methenamine silver solution applied to the ultrathin sections on nickel grids after oxidation in a periodic acid. The staining results were excellent and tissue components were evenly stained with no background silver grains. This method proved to be consistent, reproducible and reliable.
