Maxillary Sinus Anatomical Variation Mimicking a Periapical Cyst

Abstract

Panoramic radiograph (PR) is widely used in dentistry, yet certain anatomical variations can mimic pathological lesions. The aim of this case report is to present a maxillary sinus variation that appeared as a cyst-like lesion on PR around a previously endodontically treated tooth, and to highlight the diagnostic value of advanced imaging in such situations. A 31-year-old systemically healthy female patient presented with pain in the left posterior mandible. During routine PR examination, a well-defined radiolucent area was incidentally detected at the apex of the previously root canal–treated maxillary right second molar. Suspecting a periapical cyst, CBCT was performed and revealed no pathology related to the tooth; instead, multiple septa were identified within the maxillary sinus. One of these septa extended toward the tooth apex, confirming that the cyst-like appearance on PR resulted from anatomical variation combined with radiographic superimposition. This case illustrates that cyst-like areas observed on PRs are not always indicative of disease. Maxillary sinus septa and other anatomical variations can lead to diagnostic misinterpretation. Three-dimensional imaging plays a crucial role in differential diagnosis, helping clinicians avoid unnecessary invasive procedures.