Pituitary carcinomas are exceptional tumors and constitute 0.1 to 0.2% of pituitary tumors. Their definition includes well-established criteria but distant metastasis is the hallmark required for diagnosis. We report the fourth case of gonadotropic pituitary carcinoma described in the literature. This case illustrates the dramatic outcome of these tumors. The most interesting feature of our case was the loss of differentiation with time, established by retrospective analysis of the primary tumor surgically treated 15 years earlier. Most of the previously reported cases exhibited a majority of adrenocoticotropin and non-functioning pituitary tumors. However, the frequency of non-functioning tumors seems smaller than previously believed. In the discussion, we stress the need to detect these very aggressive tumors as early as possible and identify treatments to improve the dramatic course of these carcinomas.