Melanosis of the bladder

Acquired childhood bladder melanosis

Background

Bladder melanosis is rare. It has previously been described only in the fifth decade of life or beyond; it has not been described in childhood. Previous descriptions have generally been case reports, and so the natural history is poorly understood. Urinary symptoms present at the time of cystoscopy have frequently been attributed to bladder melanosis. A possible suggested aetiology is aberrant migration of melanocyte migration during embryogenesis.

Case presentation

We present the first case of bladder melanosis in a child. He had been under our care since the age of 5 years with urinary incontinence and at that time, had undergone cystoscopy demonstrating normal bladder mucosa. A diagnosis of idiopathic detrusor overactivity with underactive voiding had been made. After other unsuccessful treatments, intravesical botulinum toxin was proposed. At the age of 13, repeat cystoscopy prior to botulinum toxin, demonstrated widespread pigmented areas in the bladder mucosa. Histology showed bladder melanosis. Our finding is important for several reasons. This is the first reported case of bladder melanosis to affect a child. The previous normal cystoscopy in our patient would refute the explanation that bladder melanosis is a congenital condition. Furthermore, the development of melanosis on the background of stable symptoms raises the possibility that the condition may be asymptomatic.

Conclusions

This unique finding of bladder melanosis in a child has provided further insight into this rare and poorly understood condition.

The color of urine: then and now-a comprehensive review of the literature with emphasis on intracytoplasmic pigments encountered in urinary cytology

The color of urine, once considered by uroscopists to give the most important clues to the diagnosis, still can provide some diagnostic clues in modern medicine. Pigmented cells are an uncommon and surprising find in urine cytology and can at the same time provide important diagnostic clues or represent a dangerous pitfall. We present a review of the significance of pigmented cells in urine cytology. The presence of intracellular pigment granules; their color, size, shape, and variation in size and shape; as well as their staining reactions with special stains can provide useful diagnostic insight, especially when interpreted in the cytologic context (type of pigmented cell and its degree of atypicality) and patient's clinical context. The main differential diagnosis of cytoplasmic pigmented granules includes hemosiderin, lipofuscin, and melanin, each having a different pathogenesis and significance. The goal of this paper is to describe the morphological, histochemical, and ultrastructural characteristics of the pigments seen in urinary cytology, and to review the benign and malignant conditions associated with them.

Unusual case of simple urinary bladder melanosis with complete resolution

A 66-year-old man presented with a long history of recurrent attacks of urinary retention and lower urinary tract symptoms. Flexible cystoscopy showed a urethral stricture. Follow-up cystoscopy 7 years later for recurrent symptoms demonstrated unusual extensive mucosal brown to black pigmentation, which proved histopathologically to be a simple bladder melanosis. Follow-up demonstrated complete resolution over a period of 1 year with no specific treatment. In this report, we highlighted a rare bladder abnormality with uncertain natural history.