S. Letzel et H. Drexler, OCCUPATIONALLY RELATED TUMORS IN TAR REFINERY WORKERS, Journal of the American Academy of Dermatology, 39(5), 1998, pp. 712-720
Background: The study comprised 606 workers with tar-induced dermatosi
s employed in a German tar refinery. During the period from 1946 to 19
96 they were recognized as having an occupational disease. Objective:
The aim of this study was to characterize the histologic findings and
the localization of the occupational dermatosis and to determine the l
atency period of the carcinomas from the beginning of exposure in the
tar refinery to the first occurrence of malignant skin tumors. Further
more, the study aimed to check whether other skin changes were frequen
tly diagnosed in addition to known tar-induced tumors. Methods: The da
ta were collected retrospectively from the documents of the Employer's
Liability Insurance Association. Results: Surgical removal of 4754 sk
in tumors was documented up to the end of 1996 in the study. In 90% of
cases the histologic diagnosis was confirmed. Among other conditions,
this yielded 2490 precancerous stages, 380 squamous cell carcinomas,
218 basal cell carcinomas, and 182 keratoacanthomas. The skin turners
were found mainly in the facial area, as well as on the forearms and h
ands. Latency from the first exposure in the tar refinery until manife
station of tar-induced dermatosis covered a period of 57 years. Conclu
sion: In comparison to the general population, the ratio of squamous c
ell to basal cell carcinomas was shifted toward the squamous cell carc
inomas (1.7:1), Sunlight is known to be a cofactor in the pathogenesis
of keratosis, squamous cell carcinomas, and basal cell carcinomas, Ho
wever, the difference in location of these tumors shows that the role
sunlight plays in the pathogenesis of precancerous lesions and squamou
s cell carcinomas may be overvalued. The latency period from the begin
ning of exposure to the manifestation of squamous cell carcinomas coul
d not be evaluated because of an intervention bias as a result of prev
entive excisions of precancerous lesions. The frequent occurrence of k
eratoacanthomas tin 18.7% of the workers) and the early age at which t
his disease became manifest relative to the general population (median
, 55 years) indicate that employment in a tar refinery can primarily o
r secondarily cause keratoacanthomas.