INTRATUBULAR SPERMATIC SEMINOMA IN A FISCHER-344 RAT

A case of a spontaneous intratubular spermatic seminoma is described i n a 98-wk-old Fischer-344 (F-344) rat. The differential diagnosis of s permatic seminoma from the other morphological forms of the tumor was based on the recognition of 3 cell types. The tumor cells were positiv e for S-100 antigen and cytokeratin. To the best of our knowledge, thi s is the second case of a seminoma reported in an F-344 rat and the fi rst dealing with electron microscopic and immunohistochemical features of this tumor.