Spindle cell tumors resected from male patients with germ cell tumors. A clinicopathologic study of 14 cases.

We identified 14 male germ cell tumor patients (13 of whom had received prior chemotherapy) in whom distinctive neoplasms composed of spindle to stellate cells set in a myxoid to collagenous stroma containing numerous blood vessels developed. These neoplasms were cytokeratin-positive and vimentin-positive and alpha-fetoprotein (AFP)-negative. Ten patients with neoplasms of low cellularity and no mitoses have not had tumor recurrences, whereas four patients with more cellular and mitotically active tumors have experienced either recurrences or death. We recommend simple surgical excision, without additional chemotherapy, for the hypocellular, mitotically inactive cases. The transition from mitotically active spindle cell tumors to frankly sarcomatous areas in three cases indicates that these lesions may be the substratum for the development of sarcomas in some patients with germ cell tumors. Based on their histologic appearance and immunohistochemical profile, as well as preceding evidence of yolk sac tumor (YST) in 11 patients (data incomplete in 3 cases), we speculate that many of these cases represent overgrowth of a spindle cell component of YST that is selected for by chemotherapy.