Malignant phyllodes Tumor of the Breast; Presentation of an Uncommon Case and Review of the Literature

Background: Phyllodes tumours are rare fibroepithelial neoplasm of connective tissue of the breast accounting for 0.3-1% of all breast tumours with 10% of them being malignant. They resemble fibroadenomas clinically and can be mistakenly ignored. Case presentation: A 38-year-old unmarried Philipino lady presented to the primary health center with a mass in the right breast for the past year. Over the preceding 6 months, it had progressively increased in size and pain. On examination, a 5 x 3 cm firm and lobulated mass was palpated in the right upper outer quadrant. Ultrasound scan showed a solid 4.25 x 3.3 x 2.4 cm mass with heterogeneous mixed echopattern. She was referred to Surgery department where an ultrasound-guided core biopsy showed a lesion suspicious for benign phyllodes tumor. An excision biopsy revealed three foci of malignant Phyllodes on the background of fibroadenoma. A staging CT was performed which showed no evidence of lymph node involvement or distant metastasis. A simple mastectomy was performed and histopathology confirmed the diagnosis of malignant phyllodes tumor. Postoperatively, the patient is on regular follow up in the breast clinic and physiotherapy department. Conclusion: Phyllodes tumor bears specific clinical characteristics and should be considered as a differential diagnosis in any mass lesion of the breast.. Diagnosis and management are crucial in phyllodes tumor because of their malignant potential recurrence. Clinicians should be competent in distinguishing between fibroadenoma and a phyllodes tumor. Lastly, given the rarity of phyllodes tumors, there is a need to establish guidelines to incorporate regular follow up for early detection of distant metastasis.