Objective: To evaluate the mammographic features of nonpalpable spiculated lesions in order to find differentiating findings between malignant and benign pathologies. Materials and methods: Standard mammograms of 27 patients with 28 nonpalpable spiculated lesions were evaluated retrospectively. Two dimensions of dense centre of the spiculated lesions were measured and the mean dimensions were compared in analysing the malignant and benign features. Fine radiolucent lines between dense spicules were noted. Results: Thirteen spiculated lesions (46.4%) were malignant and 15 were benign. Eleven malignant lesions (84.6%) have dense centre larger than 5 mm, whereas only four benign lesions (26.7%) had a dense core larger than 5 mm. There were fine radiolucent lines parallel to dense spicules in 5 malignant lesions (38.5%) and in 13 benign lesions (86.7%). Only one invasive carcinoma and one radial scar with florid ductal epithelial hyperplasia and papillomatosis had punctate calcifications. The sensitivity and specificity of the dense core larger than 5 mm for malignancy mere 84.6% and 73.3%, respectively. The sensitivity of radiolucent lines for benign lesions was 86.7% and the specificity was 61.5%. Conclusion: When the dense centre of a nonpalpable spiculated lesion is larger than 5 mm, the probability of malignant pathology increases. The fine radiolucent lines between dense spicules may indicate benign etiology. However, there is no reliable mammographic feature differentiating benign spiculated lesions from carcinomas. Therefore, all of them should be diagnosed pathologically unless they are postsurgical. (C) 2003 Elsevier Inc. All rights reserved.