[Clinical study of eosinophilic cystitis. I. On the definition of eosinophilic cystitis. I-1. Histological observation of eosinophilic infiltration].

Eosinophilic cystitis is a disease accompanied by prominent increase in the number of eosinophils in the vesical wall, but whether it is diagnosable from the number of eosinophils has not been clear. We made histological observations in 5 cases thought to have elevated eosinophil count and 13 control cases. We counted the eosinophils in the 5 fields we considered to be the place eosinophils were most abundant under 200 times magnification, and an average of 20 to 50 eosinophils were found in each field. The ratio of eosinophils in the same field to all round cell infiltration was from 36 to 85%. In 2 of the 5 cases, more than 20 eosinophils were found in some fields and the ratio to all round cell infiltration was under 5%. In the remaining one case from 5 to 20 eosinophils were found in some fields, but the ratio to round cell infiltration was over 20%. On the other hand, in the 13 control cases, the average number of eosinophils was one per field and the ratio to all round cell infiltration was under 5% in the 5 fields we considered to be the place eosinophils were most abundant. Less than 5 eosinophils were found in any of the fields and the ratio to all round cell was under 5%. From these results, the 5 cases thought to have elevated eosinophil count were diagnosed to be eosinophilic cystitis.