Radial scars and stellate lesions as imaging abnormalities: a comparative study

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The aim of this study is to compare the imaging appearances of radial scars (RS), thought to be of questionable significance, to stellate lesions (SL), indicative of malignancy in up to 94% of cases (Burrell et al 1996). Mammographic appearances of RS may change depending on which projection is being viewed but may not for stellate lesions. RS are represented by an area of architectural distortion and exhibit a radiolucent core, long spicules and no calcifications. However, calcifications have been shown to be present in up to 45% of RS (Cardenosa et al 1991). SL comprise a dense core, short spicules and polymorphic calcifications. Mammographically, the two may be indeterminate. Ultrasound of both RS and SL may show similar traits: irregular outline, posterior shadowing and enhanced vascularity. Studies of contrast-enhanced MRI images show tumours to have rapid uptake with steady wash-out of gadolinium. However, this pattern can also be attributed to RS and there may be no significant enhancement differences between benign and malignant lesions (Stomper et al 1995). The specificity of MRI remains low.

In conclusion, imaging has very definite limitations and cannot readily or unequivocally differentiate between RS and SL.