[Axillary metastases of unknown primary carcinoma]

S.R., a 66-year old woman, was referred to our department because of an axillary mass in the right side. The patient had observed an increasing, painless swelling in the right axilla for the last two months. In the region of the right axilla in the middle axillary line an ovoid and solid tumour of 3 cm in diameter, quite well distinguishable, moving against the skin and the surrounding tissue, could be palpated. A subsequent mammography yielded an unsuspicious visualisation of both breasts and the left axilla. In the right axilla a circular solidification was detected, which then turned out on ultrasound examination to be a 2.6-cm diameter axillary lymph node. In the course of the lymph node extirpation of the right axilla two lymph nodes were dissected with histological evidence of metastatic nodes of a solid tumour, most likely in accordance with a breast carcinoma. Several immunohistochemical methods had been applied to determine the origin of the tumour cells and were thus identified as breast cancer cells. To detect primary causative carcinoma, different examinations were performed postoperatively without identifying any cancerous lesions. At least accurate research concerning the history of the patient was required to reexamine the histologic material of an operation of the right breast in 1989. The histological diagnosis of the dissected node of that time had been defined as a benign intracanaliculary papilloma in the right side without evidence of malignancy. The reexamination of the paraffin-embedded material from the operation of the right breast in 1989 revealed a lobular carcinoma of the right breast. The "occult" (undetectable) carcinoma of the breast occurs in less than 1% of all breast carcinomas. Thus it represent a rare clinical event and hence no standardised therapy schemata exist. To confirm the diagnosis of an occult carcinoma of the breast efficient reexamination of histological material from earlier breast operations indicated.