NONPALPABLE BREAST CARCINOMAS - HISTOLOGICAL AND IMMUNOHISTOCHEMICAL STUDIES OF 160 CASES

A series of 160 impalpable breast carcinomas was collected from 1979 to 1991. Mammographs showed microcalcifications (64 %), or opaque images (36 %). Surgical specimens were X-rayed during the intervention in order (i) to ascertain that the lesions detected on mammographs were removed, and (ii) to guide the pathologist in sampling tissue fragment for an appropriate microscopic evaluation of the lesions. During the intervention, the peroperation histological diagnosis was correct in 63 % of the cases, whereas malignancies were underscored in 37 %. No false positive diagnosis was recorded. A large majority (92 %) of false diagnoses stated during surgery were in situ carcinomas diagnosed as epitheliosis and invasive carcinomas diagnosed as in situ carcinomas. In 63 % of the cases the axillary lymph node could be removed during the first intervention. In 91 % of the cases ''in sano'' margins of resection were evaluated as such during the intervention. The size of tumors ranged from 1 to 60 mm (m = 10 mm - SD = 8.45), 70 % measuring less than 1 0 mm. Carcinomas were in situ (23.75 %), microinvasive (13.75 %) and invasive (62.5 %). Carcinomas were ductal (78.1 %), lobular (18.7 %) and of other types (14.2 %). A majority of intraductal carcinoma (68 %) were comedocarcinomas. Invasive carcinomas accounted for grade I in 37 % of the cases, grade II in 56 %, grade III in 7 %, ductal carcinomas and for tubular carcinomas in 15 %. Immunodetection could be performed on frozen sections in 78 cases. Tumors were receptor positive in 58 % of the cases. The greater growth fraction (Ki-67) and higher detection of HER-2/neu oncogene product were observed in comedocarcinomas. Diploid tumors accounted for 52 % of those evaluated (n = 48).