A case report of a patient with ductal carcinoma and a malignant phyllodes tumor in situ in 2 separate breasts

RATIONALE: Breast malignant phyllodes tumors (MPT) are quite uncommon. It is rarely reported that they occur in conjunction with breast cancer. We detailed a case in which an MPT and ductal carcinoma in situ carcinoma occurred simultaneously in 2 different breasts. PATIENT CONCERNS: A 79-year-old female patient was seen for a rapidly growing lump in the upper left quadrant of her breast. The lump was described as huge, hard, irregular, and palpable. MRI of the breasts revealed a big mass in the left breast and a smaller lump in the right. DIAGNOSIS: Ductal carcinoma in situ with breast MPT. INTERVENTIONS: We performed a double mastectomy. Post-operative endocrine treatment was suggested. OUTCOMES: During the 18-month follow-up period, no signs of recurrence or metastasis were seen. The ultrasound examination of the chest wall showed no abnormality. Bilateral axillary and supraclavicular ultrasonography showed no lymphadenectasis and a CT scan of the lungs showed no suspicious cancer nodules. LESSONS: It is possible for MPT and ductal carcinoma in situ to occur simultaneously in different breasts. Surgeons need to integrate clinical observations, imaging tools, and patient history to make an early diagnosis. Before undergoing surgery, a thorough examination of both breasts is required.