NONPALPABLE BREAST CARCINOMAS - HISTOLOGICAL AND IMMUNOHISTOCHEMICAL STUDIES OF 160 CASES

A series of 160 impalpable breast carcinomas was collected from 1979 t o 1991. Mammographs showed microcalcifications (64 %), or opaque image s (36 %). Surgical specimens were X-rayed during the intervention in o rder (i) to ascertain that the lesions detected on mammographs were re moved, and (ii) to guide the pathologist in sampling tissue fragment f or an appropriate microscopic evaluation of the lesions. During the in tervention, the peroperation histological diagnosis was correct in 63 % of the cases, whereas malignancies were underscored in 37 %. No fals e positive diagnosis was recorded. A large majority (92 %) of false di agnoses stated during surgery were in situ carcinomas diagnosed as epi theliosis 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 resect ion 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 t han 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 carc inomas and for tubular carcinomas in 15 %. Immunodetection could be pe rformed on frozen sections in 78 cases. Tumors were receptor positive in 58 % of the cases. The greater growth fraction (Ki-67) and higher d etection of HER-2/neu oncogene product were observed in comedocarcinom as. Diploid tumors accounted for 52 % of those evaluated (n = 48).