Cytodiagnostic problems in uterine sarcoma. Analysis according to a novel classification of tumor growth types.

OBJECTIVE: To clarify the cytologic diagnostic problems of uterine sarcomas and the differential properties between pure sarcomas and carcinosarcomas. STUDY DESIGN: Four leiomyosarcomas and 21 carcinosarcomas (homologous and heterologous) treated at the Saitama Cancer Center from 1991 to 2000 were analyzed macroscopically and microscopically. RESULTS: Of 4 leiomyosarcomas, 3 were intramuscular, localized type, with a negative diagnosis for sarcoma. Of 21 carcinosarcomas, 7 were exophytic type with little necrosis (B-1), 5 were exophytic type with marked necrosis (B-2), 6 were exophytic type with a small sarcomatous component (B-3), and 3 were endophytic type (B-4). All endometrial smears were positive for sarcoma in B-1, whereas 5 of 14 (36%) were positive in the latter 3 types (B-2, 3 and 4). CONCLUSION: In pure leiomyosarcomas, the sarcomatous portions are usually covered with normal endometrium. In carcinosarcomas, sarcomatous component is relatively limited in some cases and frequently covered with marked necrosis or carcinomatous tissue. These pathologically specific findings should make cytologic diagnosis difficult in uterine sarcomas.