BackgroundPhyllodes tumour is a rare biphasic neoplasm of the breast that mostly affects middle aged women. Ductal carcinoma in-situ and microcalcifications occurring within phyllodes tumours are documented but are rare findings. Primary surgical excision with adjuvant therapies remains the mainstay of treatment.Case presentationWe report a case of a 42-year-old woman with high-grade ductal carcinoma in-situ within a borderline phyllodes tumour. Radiologically, clumps of microcalcification were detected within the lesion. Local excision followed by total mastectomy with axillary dissection was then performed. No tumour recurrence was detected up to a period of 8 years.ConclusionPresence of microcalcifications within a phyllodes tumour should alert clinicians and pathologists of possible coexisting carcinoma components. Stromal and epithelial components of these lesions should be evaluated separately when formulating a management plan.