Pseudomelanosis of the bladder: a case report.
BACKGROUND
Pseudomelanosis is due to deposition of pseudomelanin and is best known as the entity pseudomelanosis coli. However, pseudomelanosis in the urinary tract has never been described. Pigmentation of the urothelium, known as melanosis vesica, is characterized by deposition of melanin pigment granules without signs of atypia. Simple (true) melanosis of the bladder is uncommon.


METHODS
A 52-year-old man presented with macroscopic hematuria. Cystoscopy and microscopic evaluation revealed pigmentation of the bladder urothelium diagnosed as pseudomelanosis vesica due to deposits of melaninlike pigment in the absence of detectable melanocytes and detectable by urine cytology.


CONCLUSIONS
Pseudomelanosis vesica is a benign lesion that has never before been observed in the urinary tract.
Wieringa
Roos E
RE
Department of Urology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
Blaauwgeers
Hans J
HJ
van Andel
George
G
D006801:Humans; D008297:Male; D008548:Melanosis / Q000473:pathology*; D008875:Middle Aged; D001743:Urinary Bladder / Q000166:cytology / Q000473:pathology*; D014556:Urine / Q000166:cytology; D019459:Urothelium / Q000473:pathology