The significance of atypia within teratomatous metastases after chemotherapy for malignant germ cell tumors.

The completely resected teratomatous metastases of 55 patients who had been treated with cisplatin-based combination chemotherapy for non-seminomatous germ cell tumors were reviewed to see if cellular atypia had an effect with respect to recurrent disease. The degree of atypia of the epithelial and mesenchymal elements was assessed on the basis of the cytologic features and mitotic activity. Twenty-three percent of the cases contained high-grade epithelial elements, whereas high-grade mesenchymal elements occurred in 18% of the cases; in addition there were nine cases classified as showing frankly malignant teratomatous elements. The presence of cytologically disturbing epithelial and mesenchymal elements (which, however, lacked an invasive malignant pattern) correlated with an increased incidence of recurrent teratoma compared to less atypical teratomatous elements (23% vs. 6% for epithelial elements, and 18% vs. 9% for mesenchymal elements, respectively). This difference, however, was not statistically significant (P greater than 0.05). There was no correlation between teratomatous atypia and recurrent, non-teratomatous germ cell tumor. The presence of an invasive malignant pattern did identify patients at significantly increased risk for recurrent teratoma-derived tumor. The authors conclude that cytologic atypia in the absence of invasion is not sufficient justification for altering the usual therapeutic strategies for patients with teratomatous metastases.