Remember our last article, Doctor, where we discussed Antral Exostosis? We described it as a bony protrusion securely attached to the floor of the maxillary sinus. Now, let’s imagine a slightly different scenario. You open a panoramic X-ray for a patient and once again spot something white and rounded inside the maxillary sinus. This time, however, it appears to be floating, almost like a small ball moving independently.
Here, the story changes completely, and we’re actually talking about something entirely different: an Antrolith.
What Exactly is an Antrolith?
Simply put, Doctor, an antrolith is a calcification that forms within the maxillary sinus. This calcification typically develops as a result of prolonged accumulation of mucus or due to the presence of foreign bodies, such as small tooth fragments that might have accidentally dropped into the sinus cavity.
How Does It Look on X-rays? Radiographic Features
To easily differentiate an antrolith from other entities, pay close attention to these details on the radiograph:
Location
You’ll find it situated within the maxillary sinus cavity itself, not attached to the bone.
Edge
Its borders are generally well-defined and can appear either smooth or irregular.
Shape
Antroliths typically present as round or ovoid structures.
Internal Structure
Internally, they are radiopaque, meaning they appear opaque to X-rays. Occasionally, they exhibit a very distinctive appearance known as a laminated appearance. This looks like alternating radiopaque and radiolucent bands, much like the layers of an onion.
Number
It’s possible to find a single antrolith, or sometimes, multiple ones.
Key Insights You Must Know
Antroliths form through the gradual deposition of calcium salts. That layered, “onion-skin” laminated appearance is one of their most telling characteristics. Their size can vary significantly, ranging from very small to quite large. While they can often be asymptomatic, they might also cause sinus-related symptoms.
What’s Its Clinical Significance?
Most often, discovering an antrolith is purely an incidental finding—you’re typically taking an X-ray for a completely different reason. However, if an antrolith grows to a significant size, it can indeed lead to sinusitis or other sinus-related symptoms. Should it cause symptoms or impair the function of the sinus, removal might become necessary. Of course, it’s also critically important to differentiate it from other pathologies that could affect the maxillary sinus.
An Important Diagnostic Note
Crucially, Doctor, you must examine multiple images (radiographic views) to definitively confirm that this radiopaque mass is not attached to the sinus borders. If, across multiple X-rays, it appears connected to the bone, then you absolutely must consider the alternative differential diagnosis: an antral exostosis or antral projection.
