OBJECTIVETo summarize the experience of diagnosis and treatment of occult breast cancer in 44 cases.

METHODSClinicopathological data of 44 cases of occult breast cancer initially presenting axillary mass alone treated in our department during Jan 1997 to Dec 2008 were retrospectively analyzed.

RESULTSThe 44 patients with occult breast cancer accounted for 0.42% of all breast cancer patients admitted to our hospital and institute in the same period. The surgery included radical mastectomy in 16 cases, modified radical mastectomy in 19 cases, axillary clearance in 1 case, and simple axillary node excision in 8 cases. Follow-up, ranging from 12-132 months, was available in 38 cases. Among 32 cases who underwent mastectomy or axillary clearance, 2 cases died of distant metastases and 3 cases were still alive with local recurrence at the time of analysis. In two out of six cases who refused further surgical treatment received mastectomy 16 months and 41 months after the primary diagnosis of occult breast cancer, respectively. Others were alive without evidence of recurrence or metastases at the time of analysis.

CONCLUSIONSOccult breast cancer should be taken into consideration in cases presenting with axillary metastasis of unknown primary origin. The treatment of occult breast cancer should include modified radical mastectomy/radical mastectomy or breast conserving surgery combined with breast irradiation.