[Two Cases of Stromal Sarcoma of the Breast]

Stromal sarcoma of the breast is a very rare disease accounting for 0.03%of primary breast malignant tumors. From 1995 to 2014, 384 patients with primary breast malignant tumors underwent resection at our institution, of which 2 cases(0.5%) were stromal sarcoma of the breast. Case 1: A woman aged in her 50's presented with a painful lump spanning the right breast identified 7-8 months previously by palpation. The patient first visited the outpatient department at our hospital when the lump gradually increased in size and bleeding from the breast was observed. The tumor measured 8 cm in its greatest dimension and it was elastic soft with a smooth surface, exhibited sphericity, and existed in combination with a partial skin ulcer. Biopsy indicated possibility of stromal sarcoma; therefore, simple mastectomy was performed and the patient was pathologically diagnosed with stromal sarcoma. Presently, the patient is alive and recurrence-free 3 years after the surgery. Case 2: A woman aged in her 80's presented with a left breast tumor identified 4-5 days previously via palpation. The patient visited a general practitioner who referred her to our hospital. The tumor measured 1.6 cm in its greatest dimension and it was elastic hard, irregular in shape, and exhibited dimpling. Biopsy indicated the possibility of malignancy; therefore, a partial resection was performed and the patient was pathologically diagnosed with stromal sarcoma. After 6 months, another lesion was detected and extirpation was performed. A recurrent lesion was detected after 7 months and extirpation was performed again. Presently, the patient is alive and recurrence-free 17 months after the third surgery. In stromal sarcoma of the breast, surgical resection with a negative margin is the only curative treatment. Tumor resection should be planned carefully and the possibility of sarcoma in breast tumors with atypical features as breast cancer should be considered.