Smooth Muscle Tumours of the Uterine Corpus: a Clinicopathologic Study with Immunohistochemical Aspects

Abstract

Background: Based on a clinicopathologic study conducted at the University of Rostock, Germany, between 1/1997 and 6/2003, the histological records of 1761 patients who had been hysterectomized were evaluated. 1422 of these patients were suffering from smooth muscle tumours: 1389 were diagnosed as multiple leiomyomas, 26 as leiomyomas of uncertain malignant potential and 7 as leiomyosarcomas. Patients and Methods: The data about the microscopic findings were obtained by use of both conventional histology (HE and Giemsa) and immunohistochemistry with markers for leiomyosarcomas (desmin, actin, sm-actin, myoglobin, vimentin, MIB1) and evaluated by statistical methods. Three case reports are also presented: 2 patients with leiomyosarcoma and 1 patient with an UMP tumour. Results: The statistical evaluation included the frequencies of the different tumours subdivided into age groups, their localizations (with 23 distinctions), the associated microscopic findings (with 12 distinctions and most important combinations) and, finally, the number of tumours per patient and their (grouped) sizes. The case reports showed the presence of nuclear atypia, a heightened mitotic index and tumour cell necrosis. Immunohistochemical methods confirmed the histological diagnosis of a leiomyosarcoma. Conclusion: In accordance with earlier studies, more than 95% of the smooth muscle tumours were leiomyomas. Leiomyosarcomas were rare (<1% in our study). In 3 out of 7 cases, a leiomyosarcoma had its origin in a leiomyoma.