Localization of an Occult Primary Breast Cancer with Technetium-99m Sestamibi Scan and an Intraoperative Gamma Probe.

Breast cancer presenting as axillary adenopathy without radiographic or clinical breast abnormality is a rare entity accounting for less than 1% of all breast cancers.[1,2] In the past, extended searches for an extramammary site were conducted, but this extensive workup was unproductive and therefore not recommended.[3] Most authors currently advise that carcinoma found in an axillary node in a woman should be treated as breast cancer even in the absence of clinical or mammographic findings.[3] The recommended treatment is mastectomy. Tumors that are not recognized by mammography or clinical observation have been treated recently with breast preservation consisting of total breast irradiation with 50 Gy to 55 Gy. A 12% local recurrence rate was found compared with 56% in the nonirradiated breast. [4] A specific and sensitive diagnostic modality to locate an occult tumor is needed for breast conservation.