Fig.1: Chest radiograph shows a suspicious nodule in the right lower lung. Fig.2: Repeat exam with nipple markers (arrowheads) confirmed the nodule to be a nipple shadow. Note that the left nipple shadow is visualized on this exam but not on the previous one performed on the same date.
Classic Nipple Shadows
- Bilateral symmetric
- Fuzzy margins with radiolucent halo, or sharp lateral but poorly defined medial margins
- Characteristic location (fifth or sixth anterior ribs or near bottom of breast shadow)
- Not present on a very recent film
- Could be identified on lateral film
- Nipple shadows can be seen in up to 10% of chest radiographs
- Although most of these can be resolved as 'classic nipple shadows' and no further imaging is needed, about 1.4% need repeat examination
- Repeat examinations are related to increased cost, time and burdensome to patients
- A 1.5 mm lead shot that, given its size, should not obscure a true pulmonary nodule
- Very helpful to determine whether the suspicious nodule is actually a nipple shadow, or not.
- Chance of having a true pulmonary nodule lying beneath the nipple shadow is very slim
Miller WT, et al. The troublesome nipple shadow. AJR 1985 (September)