nodule
Meaning of nodule: Most are found by accident on imaging ordered for something else entirely, and most of those turn out to mean nothing at all.
Definition of nodule
A nodule is a small, rounded lump of tissue that stands apart from the tissue around it, whether felt through the skin or seen on imaging. The word describes shape and size only. It makes no claim about the cause, and a nodule may turn out to be scar, old infection, a benign growth, a pocket of fluid or a cancer.
How is a nodule different from a mass?
By size alone, and where the line falls depends on the organ. In the lung a rounded shadow up to about three centimeters across is called a nodule and anything larger a mass, a boundary drawn because the larger a lesion is, the more likely it is to be malignant. On the skin the comparison runs the other way: a small raised spot is a papule, and a nodule is the larger, deeper lump that can be felt extending below the surface. Neither convention says anything about what the lump contains. Both simply give clinicians a shared vocabulary, so that a description written by one person means the same thing when read by another.
Where do nodules commonly turn up?
| Site | How it is usually found | What it commonly turns out to be |
|---|---|---|
| Lung | Chest imaging done for another reason | Healed infection or scar in the great majority |
| Thyroid | Felt in the neck, or seen on a scan of something else | A benign overgrowth or a fluid filled sac |
| Skin | Noticed or felt directly | A cyst, an inflamed area, or a growth of one skin layer |
| Vocal cords | Investigation of a persistently hoarse voice | Thickening from heavy or strained voice use |
What decides whether one is watched or sampled?
Features of the nodule and features of the person, taken together. Size counts, and so does change over time, since something unchanged across years is behaving very differently from something that has grown. The edge matters: smooth and well defined suggests one set of causes, ragged or spiculated another. Density counts, and a nodule containing calcium in a settled pattern is usually old and inactive. Against that sit the individual's own history, including smoking, previous cancer and exposures. Thyroid nodules add a further test, because a scan can show whether a nodule is making hormone. A hot nodule, which takes up tracer avidly, is very seldom malignant, while a cold nodule, which takes up little, is far more often benign than not but carries enough possibility to be looked at more closely.
Used in a sentence
A small nodule was identified incidentally on the chest imaging obtained for an unrelated injury.
Good to know
A nodule found incidentally on imaging performed for an unrelated reason is more often benign than one identified while investigating a specific related symptom, though further evaluation still depends on its individual features.
Word origin
Where “nodule” comes from
From Latin nodulus, a diminutive of nodus, meaning knot.