Eosinophilic cystitis. A study of 16 cases.

The authors describe 16 examples of eosinophilic cystitis. Cases were predominately in older men, and usually were associated with other conditions of the bladder or prostate. In contrast, most of the 21 cases reported in the English language were in women and children who had a low incidence of associated bladder conditions, but often had allergic disorders and eosinophilia. It appears that either bladder injury or allergy predisposes to eosinophilic cystitis. The bladder-injury type probably occurs fairly commonly and can be misdiagnosed both clinically and pathologically. In most of the present series, the clinical diagnosis was carcinoma of the bladder, and some biopsy specimens superficially resembled specimens from cases of nonspecific chronic inflammation. There was muscle necrosis in most examples, and significant replacement fibrosis of muscle in all the latter sometimes masquerading as mucosal fibrosis. Giemsa stain for eosinophils and trichrome stain for muscle fibrosis are helpful diagnostic aids. Also, eosinophilic cystitis appears related to allergic cystitis and interstitial cystitis.