The histiocytes seen in malakoplakia are called von Hansemann histiocytes and have abundant eosinophilic, granular cytoplasm. Michaelis-Gutmann (MG) bodies are basophilic, targetoid, intra-cytoplasmic bodies and are the main, but not obligatory, diagnostic feature of malakoplakia. They are thought to represent the result of bacteria-laden phagolysosomes that have had calcium pumped into them. The calcium is thought to precipitate with phosphate-containing components of the bacterial wall. MG bodies stain positively with von Kossa (for calcium) and Perls' staining (for iron).
- ↑ Michaelis L & Gutmann D. Ueber Einschlüsse in Blasentumoren. Zeitschrift für klinische Medizin 1902;47:208
- ↑ Dasgupta P, Womack C, Turner AG, Blackford HN. Malacoplakia: von Hansemann's disease. BJU international. 1999 Sep; 84(4):464-9.