[Clinically occult invasive cancers of the breast. Apropos of 136 cases].

Between 1978 and 1991, one hundred and thirty-six surgical excision biopsies were performed in our institution for clinically occult breast cancers. A retrospective analysis of histopathologic characteristics was carried out in order to determine the prognostic factors of these cancers detected by mammography. Mammographic findings consisted of microcalcifications alone (49 cases), microcalcifications with opacity (20 cases), stellate opacity (52 cases) and well-circumscribed opacity (12 cases). Preoperative localization was achieved by mammography in 109 cases and ultrasonography in 27 cases. The size of malignant lesions ranged from 3 to 25 mm, 76 lesions were less than 10 mm in diameter. The histopathologic findings were as follows: invasive ductal cancer (IDC) 113 cases (83%), invasive lobular cancer (ILC) 11 cases (8%), ductal or lobular cancer in situ with microinvasion 12 cases (9%). Breast conserving treatment was performed in 106 cases (78%). A high proportion of well differentiated tumors was encountered-59 grade I (52%) were identified out of 113 IDC-and the incidence of axillary node metastases was less than 10%. Clinically occult breast cancers seem to exhibit favorable prognostic factors.