Ductal carcinoma in situ presenting as a stellate lesion on mammography

Ductal carcinoma in situ (DCIS) usually manifests as microcalcification on mammography, but several other unusual forms of presentation on mammography are also described. One such atypical appearance is the stellate mass without calcification. This may occur with DCIS alone or when DCIS is associated with a complex sclerosing lesion (CSL). We retrospectively analysed the histopathological specimens and mammograms of women who were referred for biopsy from two large breast screening programmes, and were found to have DCIS as the dominant histological lesion. Of 677 women referred for surgical biopsy, 86 (13%) showed histological evidence of DCIS as the predominant lesion, and of these, seven (8%) showed a stellate appearance on mammography without associated calcification. In three cases the mammographic appearance was due to DCIS alone, and four were due to a CSL with associated DCIS. Only one case showed microinvasion (< 1 mm), and this was not large enough to account for the stellate lesion. We advocate biopsy of all radial lesions which are not surgical scars, as malignancy associated with benign lesions such as CSLs could be missed by cytological sampling errors.