Nephrogenic metaplasia (adenomatoid tumors) of bladder

Our plain-English summary of Nephrogenic metaplasia (adenomatoid tumors) of bladder, by J.A. Kaswick, J. Waisman, W.E. Goodwin (Urology, 1976).

The study

• Authors: J.A. Kaswick, J. Waisman, W.E. Goodwin
• Journal: Urology
• Published: 1976;8(3):283-6
• Type of article: Case report
• Cited by: 32 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Two cases of rare nephrogenic metaplasia of the bladder (adenomatoid bladder tumor) support the theory that these tumors originate as an atypical metaplastic response of urothelium to chronic infection or irritation. That these may also represent mesonephric or mesothelial choristomas is considered. Although benign, they may recur. Therapy should consist of antibiotics and transurethral resection or fulguration.

In plain English

This 1976 article reported two patients at the UCLA Hospital who developed nephrogenic metaplasia (also called adenomatoid tumor or nephrogenic adenoma) of the urinary bladder, which the authors described as a benign lesion. The article does not concern asbestos and mentions no asbestos exposure. The first patient, a 57-year-old man with a 25-year history of recurrent urinary stones and multiple operations, had two papillary bladder tumors removed in 1969 and a small recurrence later. No visible recurrence was present in January 1975. The second patient, a 47-year-old woman with a urethrovaginal fistula after bladder neck surgery and urinary infections, developed multiple papillary bladder tumors in 1974. Neither lesion showed signs of cancer under the microscope. The authors counted 28 reported cases, including their own: 23 men and 5 women. The authors concluded that their cases appear to support the theory that these lesions are a reaction of the bladder lining to chronic inflammation or irritation. They considered it likely that these bladder lesions are unrelated to adenomatoid tumors of the genital tract, which other studies link to mesothelial tissue.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Case report of two patients, with a brief tally of previously reported cases from the literature
• Who was studied: Two patients treated at the UCLA Hospital, Los Angeles. The first was a 57-year-old man with recurrent urinary stones, whose tumors appeared in 1969 and who was followed to January 1975. The second was a 47-year-old woman referred in June 1973 with a urethrovaginal fistula, whose tumors appeared in October 1974.
• Exposure: No asbestos exposure is mentioned. The authors linked the lesions to prolonged, complicated urologic treatment and to chronic infection or irritation, including stones, operations and urinary infections.
• Main results:
  • Case 1 (the man): two papillary tumors were removed through the urethra in September 1969, and a tiny recurrence was removed about a year after an October 1970 cystoscopy. No visible recurrence was present in January 1975.
  • Case 1 under the microscope: no significant cell atypia, and no dividing cells were seen.
  • Case 2 (the woman): multiple papillary bladder tumors were found in October 1974 and treated by transurethral resection and antibiotics. Her cell nuclei were larger and more irregular than in case 1, but there was no histologic evidence of malignancy.
  • Of the 28 reported cases, including the authors' two, 23 were men and 5 were women. Ages ranged from 18 to 71 years, and more than 60 per cent were under fifty.
  • The authors had recently seen two more patients with this lesion at an affiliated hospital (Harbor General Hospital, Torrance, California).
• The authors' conclusion: The authors concluded that their two cases appear to support the inflammatory theory of origin, though a combination of the inflammatory and embryologic theories may be the most plausible explanation. They regarded the lesions as benign. They considered it likely that the bladder lesions are not related to genital tract adenomatoid tumors, which other studies tie to mesothelial origin.

Topics

Medical terms in this study, explained in our Lexicon: Adenomatoid Tumor.

Related studies

• Nephrogenic adenoma: a form of adenomatous metaplasia of the bladder. A clinical and electron microscopical study — E.A. Molland, P.A. Trott, et al. (1976)
• Nephrogenic metaplasia of the bladder — E.B. Sussman, M. Brice, et al. (1974)
• Nephrogenic adenoma of the bladder in children — S.R. Nold, W.J. Terry, et al. (1989)
• Occupational cancer of the urinary bladder in dyestuffs operatives and of the lung in asbestos textile workers and iron-ore miners — G.M. Bonser, J.S. Faulds, et al. (1955)
• Nephrogenic adenoma of bladder — S.I. Tannenbaum, S.A. Kramer, et al. (1980)
• Nephrogenic adenoma of bladder — E. Kaany, S.L. Werner (1974)

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