Nipple Shadows?

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

Problems

• 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

Nipple Markers

• 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

Reference:
Miller WT, et al. The troublesome nipple shadow. AJR 1985 (September)