[Occult cancer as a special form of breast carcinoma]

Occult carcinoma of the breast is characterized as a diagnosis made when the finding of axillary metastasis precedes the identification of the primary mammary lesion. This concept must be distinguished from subclinical breast cancer, in which a non-palpable tumor is discovered through radiological image. In 1975, a 56 years old patient presented an axillary metastatic lesion not detected by a conventional mammogram, but revealed by specialized equipment. After a modified radical mastectomy performed at that time, she has remained asymptomatic for 14 years. In 1985, a 51 years old patient, had an axillary clearance after a diagnosis of a malignant lymph node without the identification of the primary lesion on her homolateral breast, in spite of several tests. After 40 months, during her frequent follow-up, a small lump was identified by mammography. The patient underwent a quadrantectomy followed by radiotherapy and is asymptomatic after 2 years. These 2 cases, added to others mentioned in international literature, allow us to consider occult breast carcinoma as a particular type belonging to the special category of Unknown Primary Tumors (UPT), in which the biologic aspects and prognostic index authorize a less aggressive management than is usually accepted for the UPTs.