CLINICALLY OCCULT INVASIVE BREAST CANCERS - A SERIES OF 136 CASES

Between 1978 and 1991, one hundred and thirty-six surgical excision bi opsies were performed in our institution for clinically occult breast cancers. A retrospective analysis of histopathologic characteristics w as carried out in order to determine the prognostic factors of these c ancers detected by mammography. Mammographic findings consisted of mic rocalcifications alone (49 cases), microcalcifications with opacity (2 0 cases), stellate opacity (52 cases) and well-circumscribed opacity ( 1 2 cases). Preoperative localization was achieved by mammography in 1 09 cases and ultrasonography in 27 cases. The size of malignant lesion s 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 %). B reast conserving treatment was performed in 106 cases (78 %). A high p roportion of well differentiated tumors was encountered - 59 grade 1 ( 52 %) were identified out of 113 IDC - and the incidence of axillary n ode metastases was less than 10 %. Clinically occult breast cancers se em to exhibit favorable prognostic factors.