Most breast metastases of extramammary malignancies are lymphoma, leukemia and melanoma. And the portion of breast metastases of lung cancer is even rarer. Recently, I encountered this rare malignancy. A 63-year-old female patient, who wasdiagnosed as non-small cell lung cancer six years ago, presented with a hypermetaboliclesion in the breast on follow-up positron emission tomography. The lesion turned out to be metastasis of squamous lung cancer.