A 53-year-old woman presented with a right breast lump identified approximately 6 months previously on palpation. Because the lump gradually increased in size, she initially visited a general practitioner who referred her to our hospital. Mammography and breast ultrasonography revealed a lesion in the right breast. Biopsy indicated a case of stromal sarcoma. Three months later, another lesion was detected, and simple mastectomy was performed. A recurrent lesion was detected after 1 month, and lumpectomy was performed. Another mass developed 1 month later, and extirpation was performed. After 1 month, another mass was detected, and extirpation was performed again. The stump was negative for lesions and recurrences. A thorough examination did not reveal metastasis to remote organs. There are no established therapies for stromal sarcoma. Surgical excision is undoubtedly indicated, as observed in this patient who showed multiple recurrent lesions despite the surgeries performed.