Invasive lobular carcinoma of the breast (ILC) is the second most common form of mammary neoplasm after ductal carcinoma. Due to its histological features, characterised by a diffuse infiltration of the tissue by malignant cells with scarce fibrotic reaction, lobular carcinoma often presents clinical and instrumental diagnostic difficulties. The Authors present a retrospective series of 28 patients with lobular carcinoma, with special regard to the diagnostic work-up. Clinical examination misdiagnosed 10 cases, in which only a mild thickening of the breast parenchyma was present. Mammographic false negatives were 21.4% (6 cases). Ultrasonography allowed correct diagnosis in 5 out of these 6 cases. Fine needle aspiration (FNA) had low sensitivity (33% false negatives). ILC constitutes a diagnostic challenge, often requiring the combination of multiple diagnostic tools.