A case of eosinophilic granuloma of the urinary bladder

Background: Eosinophilic granuloma of the urinary bladder is extremely rare. We report a case with Langerhans cells in urine. Case: A 61-year-old woman with microscopic hematuria and mild cystitis was found in urine cytology to have scattered loosely packed or isolated histiocytoid cells and a small number of eosinophils with indistinct eosihophilic granules. Histiocytic cells had typical indented nuclei. Cystoscopy showed multiple small elevated lesions. Biopsy showed proliferation of histiocytic cells with grooved and indented nuclei and infiltration of eosinophils and lymphocytes. Immunohistochemically, histiocytic cells were positive for S-100 protein and negative for CD 68 and lysozyme, yielding a histological diagnosis of eosinophilic granuloma. It is very important to differentiate Langerhans cells from other similar cells. Conclusion: Langerhans cells show characteristic features in cytology, so cytological examination is useful for diagnosing eosinophilic granuloma.