THE MAST CELLS 



described in chronically infected or hypertrophied nerve sheaths (Rosenheim, 

 1886; Unna, 1894; Greggio, 1911), in fibrotic adrenals (Sabrazes and Husnot, 

 1907), in rheumatic myocarditis (Hamilton and Syverton, 1950) and are 

 particularly numerous at the base of chronic peptic ulcers (Quensel, 1928; 

 Janes and McDonald, 1948; Corbetta, 1951; Squartini et al, 1956). They are 

 frequently seen in chronic inflammatory conditions of the skin (Asboe-Hansen, 

 1950; Prakken and Woerdemann, 1952). Both Ehrlich (1879) and Westphal 

 (1891) were impressed by the abundance of mast cells in 'brown induration ' 

 (haemosiderosis) of the lung. However, they and many later authors agree 

 that in acute inflammation the mast cells temporarily disappear (Neumann, 

 1890; Neuberger, 1894; Maximow, 1904; Ernst, 1926; Stockinger, 1927; 

 Brodersen, 1928; Quensel, 1933; Larsson and Sylven, 1947; Drennan, 1951; 

 Gustafsson and Cronberg, 1957; McGovern, 1957). Later, as the acute 

 inflammation subsides and as spindle-shaped fibroblasts elaborate their fibrils, 

 there occurs a progressive increase in the number of mast cells in the affected 

 area; and as long as this proliferative phase persists the local mast-cell popula- 

 tion continues to increase (Staemmler, 1921; Bensley, 1950). Enormous 

 numbers of mast cells are thus found in the hypertrophied connective tissue 

 of elephantiasis (Baumer, 1896; Ehrich et al, 1949). Once healing is complete 

 the local hyperaemia subsides and the fibrous tissue becomes progressively 

 less cellular, finally dry and sclerotic. As it does so the local mast-cell popula- 

 tion likewise declines until, in dense scar tissue, no mast cells remain (Ehrlich, 

 1877; Neumann, 1890; Baumer, 1896; Staemmler, 1921; Higuchi, 1930). 

 This sequence of events, seen in the connective tissues of the healing wound 

 (Maximow, 1904; Sylven, 1941; Numers, 1953; Wichmann, 1955), becomes 

 even more obvious during the life cycle of keloid (Pautrier and Woringer, 1931 ; 

 Sylven, 1941, 1945; Asboe-Hansen, 1951). 



Examination of the status of the mast cell in the inflammatory process 

 thus supports Ehrlich's view that there appears to exist a functional association 

 between the mast cell and connective tissue, increasing fibroplasia merely 

 emphasizing a relationship which we have already noted in our study of the 

 mast cell in the normal organism (Riley, 1954). 



Mast cells and tumours 



Four aspects of the relationship of mast cells to tumours can be distinguished. 

 They are: — 



1 . the mast-cell reaction to established tumour growth ; 



2. tumours rich in mast cells; 



3. tumours composed of mast cells; 



4. the mast cell in carcinogenesis. 



22 



