Ultrastructural features in a case of ureteric malakoplakia

The ultrastructural features of malakoplakia

The ultrastructural features of a case of disseminated malakoplakia are described and compared with available published cases. Generally macrophages were involved (although characteristic inclusions were seen in association with some plasma cells) and contained three types of cellular inclusions. These were (1) the phagolysosomes (2) and intermediate structure sharing features of the phagolysosome and the Michaelis-Gutmann (MG) body and (3) the MG body. All inclusions were delineated by unit membranes and their matrices (except those of large MG bodies) composed of membranous whorls and loops. It is suggested that these inclusions represent stages in the development of the MG body. Septate junctional complexes were observed between phagolysosomes and small MG bodies. These complexes may represent either a mechanism of organelle fusion or an abnormality of molecular organisation of the limiting unit membrane.

An unusual case of supraclavicular and colonic malakoplakia--a light and ultrastructural study

A case of malakoplakia of the supraclavicular region and colon in a 41-year-old patient is presented. Clinical, histopathological, histochemical and ultrastructural features are described. The etiology and pathogenesis are discussed. Malakoplakia is a chronic inflammatory disorder probably due to an abnormal response to infection with Gram negative bacteria, most likely Escherichia coli or Klebsiella. The disease is characterised by the accumulation of macrophages intermixed with plasma cells and lymphocytes. The malakoplakic cells are laden with phagolysosomes which may provide a suitable biochemical environment for the deposition of calcium to form the pathognomonic Michaelis-Gutmann bodies. Ultrastructural examination enhances the accuracy of diagnosis since it highlights the presence of lysosomes, phagolysosomes, Michaelis-Gutmann bodies, and intact E. coli or their remnants.