Author reply

Abstract

The comments by Dr. Renshaw raise the interesting question of whether the described tumor should be classified as an intratesticular leiomyosarcoma or a gonadal stromal tumor. It refers to the difficulty in classifying a group of spindle cell tumors within the category of testicular sex cord-stromal tumors. These tumors have been reported under a wide variety of synonyms.1 Renshaw et al.1 found in some of these tumors an intimate association with the rete testis. Reticulin-enveloped nests of epitheloid cells, cells with prominent nuclear grooves, and strong immunoreactivity for S-100 protein and smooth muscle actin were further characteristics suggesting the classification of these neoplasms as granulosa cell tumors. Because of these findings, we studied the illustrated neoplasm again. We could not identify an association with the rete testis. Immunohistochemically, there was a strong reactivity for desmin, muscle specific actin, and smooth muscle actin and no reactivity for cytokeratin and S-100 protein (Fig. 1). Reticulin stain revealed fibers surrounding the individual cells but not groups of cells. Using these findings, we are convinced that the original classification of the tumor as a leiomyosarcoma was correct. Immunohistochemical staining for S-100 protein. The tumor cells are negative. The arrow indicates positive S-100 protein staining in a nerve fiber. (original magnification ×180). From a theoretic point of view, a histiogenesis from undifferentiated gonadal stromal cells is possible. However, there also are arguments for a smooth muscle descent. Leiomyosarcomas arising from spermatic cord or epididymal smooth muscle elements are among the most common urologic sarcomas in adults.2, 3 Such elements also are present in the tunica albuginea, blood vessels, and the testicular parenchyma and could be a site of origin of smooth muscle tumors. Michael Froehner M.D.*, Rainer Fischer M.D. , Manfred P. Wirth M.D. , * Department of Urology, Department of Pathology, Department of Urology, University Clinics “Carl Gustav Carus”, Technical University of Dresden, Dresden, Germany