Median sigmoid depression vs. Developmental salivary gland inclusion in the mandibular sigmoid notch: A CBCT Study & Literature Review

Molly V. Makos

Makos, Molly V., Dumé, Jennifer, Mupparapu, Mel
Faculty / Advisor: Mupparapu, Muralidhar
University of Pennsylvania School of Dental Medicine, Department of Oral Medicine


Objectives: To explore the differential diagnosis of a case reported radiographic anomaly and analyze the literature surrounding potential conclusions.


Case Report: In this case report, a 71-year-old Caucasian female presented for treatment to Penn Dental Medicine for comprehensive dental treatment. The panoramic radiographic examination revealed an asymptomatic, semicircular radiolucency with a well-defined, corticated border in the mandibular sigmoid notch. A CBCT was then obtained to visualize the sigmoid notch in 3-dimension.


Discussion: Medial sigmoid depression (MSD) is radiographically described as a well-defined radiolucency located specifically in the inferior aspect of the sigmoid notch. Considered a normal anatomic landmark, MSD is commonly misinterpreted on panoramic radiographs as cystic pathology. Stafne bone cavity (SBC) or Stafne bone defect is a rare mandibular bony defect that was first reported by Edward C. Stafne in 1942. Stafne bone cavity most commonly presents as an asymptomatic unilocular well-circumscribed round or ovoid radiolucency. This bony defect has been found near the molar region of the mandible, the angle of the mandible, and the ascending ramus.


Conclusions/Clinical Significance: Based on the diagnostic imaging and anatomic location of the anomaly, this case report describes a differential diagnosis of either an MSD or the first reported case of an SBC found in the mandibular sigmoid notch. Further invasive testing –specifically sialography –would be needed to determine a definitive diagnosis. Both MSD and SBC are variants of normal anatomy yet can be radiographically misinterpreted as pathological entities.