CARCINOSARCOMAS OF THE FEMALE GENITAL-TRACT - A PATHOLOGICAL-STUDY OF29 METASTATIC TUMORS - FURTHER EVIDENCE FOR THE DOMINANT ROLE OF THE EPITHELIAL COMPONENT AND THE CONVERSION THEORY OF HISTOGENESIS

Carcinosarcomas of the female genital tract have generally been regard ed as a type of sarcoma. Recent evidence suggests, however, that they may be more closely related to carcinoma. The histologic features of 2 9 carcinosarcomas with documented metastases were analyzed to study th e relative importance of the carcinomatous and sarcomatous components and attempt to provide further evidence on the histogenesis of these n eoplasms. Patients' ages ranged from 33 to 81 years (mean, 68). The pr imary tumor originated in the uterus in 17 cases, the ovary in 11, and the fallopian tube in one. Heterologous sarcoma was present in 21 of the primary tumors (72%). Myometrial invasion was present in all 15 of the uterine tumors treated with hysterectomy and consisted only of th e carcinomatous component in 12 cases (80%). In two cases, which possi bly developed as ''collision''-type carcinosarcomas, the myometrium wa s separately invaded by carcinoma and sarcoma. Myoinvasive tumor consi sted solely of sarcoma in one case. Lymphatic-vascular invasion was fo und in 10 of the primary tumors (eight uterine, two extrauterine) and consisted of pure carcinoma in all instances. The cellular composition of 62 metastases was evaluated. Of these, 51 metastases were diagnose d concurrently with the primary tumor in 21 patients (73%). Eleven met astases were diagnosed from 2 to 26 months after initial treatment. Ca rcinoma only was found in 43 metastases (70%), both carcinoma and sarc oma in 15 (24%), and sarcoma alone in four (6%). A total of 35 lymph n ode metastases occurred in 10 cases, consisting of carcinoma alone at 34 sites. The sole example of a purely sarcomatous lymph node metastas is occurred in one of the possible uterine ''collision''-type tumors. Intraperitoneal metastases to serosal surfaces or the omentum occurred in 19 cases and consisted of both carcinoma and sarcoma in 14 and car cinoma only in five. Vaginal metastases occurred in four cases and con sisted of only carcinoma in two, carcinoma and sarcoma in one and only sarcoma in one. Four patients had distant organ metastases, including one each to the liver (carcinoma only), breast (carcinoma only), bone marrow (sarcoma only), and brain (sarcoma only). Of the 51 concurrent metastases, only carcinoma was present in 37 (73%), both carcinoma an d sarcoma in 13 (26%), and sarcoma alone in one. Of the 11 subsequent metastases, carcinoma alone was found in six (55%), sarcoma alone in t hree (27%), and both carcinoma and sarcoma in two (18%). We conclude t hat (a) the dominant element in carcinosarcomas of the female genital tract is the epithelial component; (b) the potential for sarcomatous d ifferentiation in metastatic lesions is enhanced in anatomic sites wit h hollow spaces that allow polypoid growth, such as the peritoneal cav ity and vagina; (c) a minority of these tumors may arise as ''collisio n''-type tumors but most probably develop as ''conversion'' tumors wit h sarcoma evolving from carcinoma; and (d) malignant mixed tumors of t he female genital tract are closely related to carcinomas and should n o longer be regarded as a subtype of sarcoma for purposes of taxonomy and possibly for purposes of treatment.