US EPA

1355105 

Journal Article 

Hyperkeratosis of the urinary bladder 

Wechsel, HW; Gotz, T; Loeser, W; Bichler, KH; Wehrmann, M 

2000 

Yes 

Aktuelle Urologie
ISSN: 0001-7868 

31 

6 

382-384 

WOS:000165305700008 

Hyperkeratosis is rare in urologic disciplines and is then
usually confined to the external genitalia. Hyperkeratotic changes within the vesicular system,
which is normally lined with urothelium, have not been previously described in the world
literature. The only connection is found in the frequent combination of palmoplantar skin
hyperkeratosis and common cancer of the urinary bladder. Localized microscopic keratinization in
leucoplakia has been described. Macroscopically visible hyperkeratosis within the urinary bladder
has not been described. We would like to introduce a 36-year-old female with this hyperkeratosis
of the bladder. Hyperkeratosis is constituted by a disruption in keratinization and a thickening
of the horny layer of the epidermis. A distinction is made between proliferative hyperkeratosis
(often the result of hornification or keratinization) and retention hyperkeratosis (brought about
by reduced desquamation). Hyperkeratosis of the skin can be evoked by exposure to various
chemical substances. In addition to transitional epithelium, squamous epithelium is also found
occasionally within the urinary bladder. Squamous cell carcinoma can result from this in up to 3%
of patients with all types of carcinoma of the bladder. Theoretically, therefore, is possible -
although unlikely - for all other changes which are observed in squamous epithelium to appear
within the urinary bladder as well. A conceivable pathogenetic mechanism in the development of
intravesical hyperkeratosis would be a change in the urinary bladder, e.g. squamous epithelial
metaplasia (rarely accompanied by intravesical squamous cell carcinoma). Keratinization is to be
expected as a further rare event during this formation of squamous epithelium, with subsequent
keratinization. Hyperkeratosis, which is otherwise found only in the area of the epidermis, must
be regarded as one such change of the squamous epithelium. The hyperkeratosis in the case
reported here was comparable to hyperkeratosis of the palms and soles, since there were no
pathohistologic signs of precancerous conditions like leucoplakia, Bowen's disease, senile
keratosis, arsenic keratosis or pitch warts. The basic pathophysiologic model has a certain
probability, but has not been confirmed. In summary, the present case was a form of
hyperkeratosis of the urinary bladder that has not: been previously described In the world
literature. In addition, there were no manifestations whatever anywhere on the surface of the
body. 

urinary bladder; keratosis