Kapronczay Károly szerk.: Orvostörténeti Közlemények 194-195. (Budapest, 2006)

TANULMÁNYOK — ARTICLES - ELEK, Gábor - MÜLLER, Miklós: Ervin Bauer as pathologist

A convincing presentation of this process (histologic images) ...was, however, not provided yet... That the surface epithelium indeed can be involved in the origin of the cystoma was impeccably demonstrated by Bauer in my Göttingen Institute on serial sections of a cystoma appearing in the form of a so called Struma ovarii" (Kaufmann 1922, 12261227). Bauer attempted to detect iodine in the colloid in the acini of the tumor but without success. On this basis he regarded the "struma" a cystoma and not a tumor containing thyroid tissue. He felt that there is no genetic difference between somatic cells and the cells of the struma ovarii and assumed this conclusion to be valid for all such tumors. Eight years later his teacher writes: "A struma ovarica cannot be distinguished in all cases easily from a pseudomucine-cystoma (it is almost always free of iodine and with usual staining methods appears as a cystadenoma (Bauer in my Institute). However, in other cases specific, more complicated staining methods can reveal a clear identity with thyroid tissue" (Kaufmann 1922, 1240). Today, it is known that struma ovarii can produce thyroid hormone (Cotran et al. 1989, 1166) and that due to their parthenogenetic origins the cells of this tumor can be genetically different from somatic cells (Kálmán and Pajor 2004, 10971098). Studying an esophageal tumor, Bauer (1917) concluded, that while such tumors can develop due to injuries, defective development or dystopy of the muscular or connective tissue, often they do not originate from these tissues but arise from undifferentiated cells of entirely different origin, also quoted by Kaufmann (1922, 502). The notion that tumors derive from cells that become located at abnormal sites during errors in embryogenesis was proposed by Cohnheim. Ribbert (1914, 44 and ff) suggested that such events can occur also in later phases of ontogenesis (e.g. tumors could originate from cells multiplying during regeneration). Bauer's criticism of the theories was well placed (e.g. Borst 1919, 747; Baló 1962, 237), but he erred in looking for the stem cells giving rise to the tumor among certain nucleated blood cells. Today it is generally accepted that tumors originate through genetic defects that occurr when cell multiplication increases during regeneration or errors of ontogenesis (Kopper 2004, 3 12; Cotran et al. 1989, 266). Based on his observations and theoretical considerations Bauer regarded tumorigenesis not an intrinsic, genetic cellular event but thought it to be due to external factors. He discusses these ideas in his general monographs (Bauer 1935) and in his later theoretical paper (Bay3p 1936) as well as in experimental papers (Bauer 1925, Bauer and Lasnitzki 1925, Bauer et al. 1936). These contributions, however, became mostly obsolete by now and will have to be discussed elsewhere. The significance of Bauer's studies in pathology for the development of his Theoretical Biology A major significance of Bauer's studies on pathology is that they provided building blocks for his theoretical considerations. A perusal of the last part (III. Teil. Anwendung der Prinzipien in der Pathologie) of his first theoretical monograph (Bauer 1920c) makes this very clear. We show this by juxtaposing selected statements from his original papers to corresponding sentences from the monograph (Table 2).