Comparative pathology of dome and trigone of urinary bladder mucosa in paraplegics and tetraplegics.
Paraplegic/tetraplegic individuals are prone to develop chronic urinary tract infection, urinary calculi and bladder outlet obstruction, and have a 16 to 28 times higher risk for squamous cell bladder cancer. The preferable method of monitoring those patients who are at high risk of developing vesical neoplasia has been an annual check-up inclusive of cystoscopy and cold cup bladder biopsy of all suspicious areas as well as predetermined random sites. It may be desirable to take a biopsy from one site (when there is no suspicious lesion) with a flexible cystoscope while the patient is sitting in the wheelchair itself in the outpatient clinic instead of multiple biopsies from the done, trigone and both lateral walls of the urinary bladder taken in the operation theatre set-up using a rigid cystoscope with the patient positioned in lithotomy. Before adopting such a cost-saving and more convenient procedure routinely, we evaluated whether any significant additional histopathological findings are obtained by taking bladder biopsies from the dome and the trigone of the urinary bladder instead of just one, be it dome or trigone in the absence of any visible urothelial lesion in the bladder. In forty consecutive tetraplegic/paraplegic patients who did not have any cystoscopically distinguishable urothelial neoplastic lesion such as papilloma, cold cup biopsies of the dome and the trigone were taken randomly before carrying out any diagnostic or therapeutic procedure, eg electrohydraulic lithotripsy of vesical calculi. All the biopsy specimens were evaluated by a pathologist who was unaware of the clinical details and not involved with the primary diagnosis. In 15 cases, significant additional histopathological finding(s) were recorded in the trigone biopsy which were not seen in the dome biopsy (follicular cystitis: n = 4; squamous metaplasia: n = 4; extensive squamous metaplasia with focal atypia: n = 1; limited focal atypia: n = 1; extensive glandular metaplasia: n = 1; intestinal metaplasia and possibly follicular cystitis: n = 1; and follicular cystitis and intestinal metaplasia: n = 1; mild atypia: n = 1; extensive calcification of epithelial denudation: n = 1). Histopathology of dome biopsies revealed significant additional histopathological finding(s) in nine cases (follicular cystitis: n = 2; squamous metaplasia: n = 2; intestinal metaplasia: n = 1; squamous metaplasia and adenomatoid metaplasia and mild atypia: n = 1; features of interstitial cystitis: n = 1; mild dysplasia: n = 1; mild crypt hyperplasia of urothelium with mild atypia: n = 1). Thus in twenty cases (50%), significant additional findings were obtained by taking cold cup random biopsy of the dome as well as the trigone in the absence of any visible morphological changes. Although single site biopsy may be less traumatic, more convenient to the patient as well as to the staff, and cost saving, in the spinal cord injury patients with neuropathic bladder, it may not be diagnostically adequate even in those patients who do not have any cystoscopically distinguishable lesion in the urinary bladder.