Malignant Phyllodes Tumor: Report of Two Cases and Review of Literature.

Phyllodes tumuor (PT) is a rare biphasic breast neoplasm. It constitutes <1% of the entire tumours of the breast. Based on the World Health Organization's (WHO) proposal, premised on multiple histological features, phyllodes tumour is categorized into benign, borderline, and malignant breast neoplasms. Malignant phyllodes tumor (MPT) is even a rarer neoplasm. It occurs more commonly in older patients. However, it can uncommonly occur in younger individuals. The transformation of benign phyllodes into malignant forms is extremely rare. Here, we present two cases of young females (aged 20 and 27 years, respectively) who individually presented with rapidly progressive breast lumps. The two breast lumps were huge while one was recurrent and underwent a malignant transformation in approximately 7 weeks interval following an initial complete excision and histological diagnosis of benign PT. Indeed, even in young females below the modal/peak age of phyllodes, the suspicion should be high. Additionally, breast ultrasonography findings, although not common, can be highly suggestive of PT. Furthermore, every breast lump should be further evaluated, and even more so, histologically, irrespective of the patient's age as our first patient had an excision without histology.