In this pictorial essay, we showcase the imaging and pathological findings of a variety of giant breast lesions. Some lesions such as lipomas and hamartomas contain fibrous, glandular and lipomatous tissues and can have characteristic mammographic appearances. Other lesions (e.g. simple cysts, fibroepithelial lesions and some malignancies) may be mammographically indistinguishable and ultrasound (US) may be helpful in further characterisation, for example, by demonstrating posterior enhancement with simple cysts, cystic and solid components in papillary lesions, internal septations on haematomas and abscesses, solid homogeneity or heterogeneity in fibroepithelial lesions and increased vascularity in neoplastic, inflammatory or infective lesions. A diagnostic needle biopsy may be performed in some cases; however, with larger and heterogeneous lesions, there is an increased possibility of diagnostic inaccuracy due to limited sampling, such that full excision of the lesion may be advisable to ensure an accurate diagnosis.