(1) Histiocytosis-X can manifest itself in virtually every organ, but in gynecology it is an absolute curiosity. (2) Differential diagnosis must exclude specific and nonspecific ulcerations and granulations such as syphilis, tuberculosis, Boeck's disease, and also neoplastic processes like lymphomas, sarcomas, carcinomas, and malignant diseases of the hemopoietic system. (3) The diagnosis by light microscopy alone, as in our case, may be insufficient; therefore, electron microscopy should be used. As soon as the diagnosis is confirmed histologically, an extensive examination of all organs is necessary in order to establish an exact prognosis and an optimal plan of therapy. (4) Because of the unknown etiology of histiocytosis-X, a causal treatment is not yet possible. In spite of this, with a symptomatic, individualized therapy by means of excision, low-dose irradiation and cytotoxic agents a 5-year survival of 90% was obtained for the patients. (5) Because of its rarity and multidisciplinary character, histiocytosis-X is a challenge to interdisciplinary and interregional cooperation. Though not being a malignoma in the strict sense, diagnosis, therapy, and in part prognosis are not essentially different from a malignant disease.