Unusual breast masses present a diagnostic challenge due to their unusual presentation or mixed imaging features, often requiring a comprehensive triple approach for accurate diagnosis and evaluation. Imaging plays a pivotal role in the assessment and management of breast masses. While clinical examination remains a fundamental diagnostic tool, imaging techniques provide crucial insights into the nature, location, and characteristics of unusual breast masses, aiding in differential diagnosis. Histopathology and immunohistochemistry definitely lead to the closest or definitive diagnosis helping accurate treatment planning. These masses encompass a gamut of breast diseases. Among malignancies, the most common type is invasive ductal carcinoma, no special type/not otherwise specified. These tumours originate from the terminal duct lobular unit. They can also feature some special subtypes like apocrine change, neuroendocrine differentiation, lobular carcinoma, etc. There are some rare variants like mucinous carcinoma, metaplastic carcinomas, and sarcomas that can also develop in the breast. This chapter mentions the unusual manifestations and imaging features of such rare neoplasms in the breast.