31) Malakoplakia is characterized by a distinctive and potentially tumefactive infiltrate of histiocytes with abundant granular pink cytoplasm (von Hansemann
histiocytes) that resemble the histiocytes of CSH.
The aneuploidy theory of cancer was introduced by David von Hansemann in 1890 and formally stated by Theodor Boveri in 1914.
The only other author at the time with similar ideas was von Hansemann.
As Hansemann said more than 100 years ago, cancer is "a new biologic entity, differing from any cell present at any time in normal [development].
It has been the impression of some that I had read the work of von Hansemann before I began my investigations.
After defending his doctoral dissertation in 1886 under the direction of Julius Cohnheim, MD, Hansemann worked as an assistant to Rudolf Virchow, MD, and then held in succession the positions of lecturer, nominal professor, and honorary professor of pathologic anatomy at the University of Berlin.
Bignold LP, Coghlan BLD, Jersmann HPA, von Hansemann DP.
Malakoplakia is thought to be an inflammatory mass-forming process, composed of sheets of granular pink histiocytes (von Hansemann
cells), which contain distinctive Michaelis-Gutmann bodies.
Malakoplakia is composed of sheets of oval histiocytes with abundant granular eosinophilic cytoplasm (von Hansemann
histiocytes) that contain basophilic, periodic acid-Schiff (PAS)-positive, diastase-resistant inclusions, and calcified Michaelis-Gutmann bodies (Figure 6).
Histologically, malakoplakia is defined by sheets of ovoid histiocytes (called von Hansemann
histiocytes or Hansemann
cells) with accumulation of 5- to 15-mm granular basophilic periodic acid-Schiff-positive, diastase-resistant inclusions (Figure 1) and calcified Michaelis-Gutmann bodies (1) (Figure 2), which are pathognomonic, although not necessary for diagnosis.
Malakoplakia was first described by Michaelis and Gutmann in 1902 and elaborated on in 1903 by von Hansemann
, who coined the term "malakoplakia," derived from the Greek malakos (soft) and plakos (plaque).