168 DOI: 10.1309/6YEPMCHACPG2BD15 © American Society for Clinical Pathology

Bilateral breast carcinomas may represent contralateral metastases or new primary tumors. The presence of carcinoma in situ, a lower grade, or a different histotype in the second tumor is considered a clinical criterion for a second primary tumor. In this study, 26 bilateral breast carcinomas from 13 patients were analyzed based on clinical criteria, and the results were compared with those obtained by partial allelotyping using 47 markers at 7 chromosomal arms. Of the 8 synchronous tumors, 5 were concluded to be distinct primary tumors using clinical criteria; some were confirmed by partial allelotyping. In the remaining 3 cases, partial allelotyping showed distinct primary tumors. Five patients had metachronous carcinomas with 3 distinct primary tumors, 1 metastasis, and 1 tha