ATYPICAL AND PROMINENT PNEUMATOCYST IN THE CERVICAL VERTEBRAE AS AN INCIDENTAL FINDING ON CBCT: A CASE REPORT

Abstract

<h3>BACKGROUND</h3> A pneumatocyst is an intraosseous gas collection. Although the etiology remains unclear, it has been associated with several conditions including osteomyelitis, trauma, osteonecrosis, and degenerative disease. They are uncommon lesions, with a reported rate varying from 0.13% to 3.9%. Pneumatocysts are more commonly seen in the sacroiliac joint and less commonly seen in the spinal vertebrae. <h3>CASE REPORT</h3> We present a case of a 61-year-old male patient who was referred for evaluation of the mandibular left lateral incisor for implant placement. Upon radiographic examination using a cone beam computed tomography (CBCT) scan, we found a prominent well-localized, hypodense entity in the body of C3 as an incidental finding. The size of the entity was approximately 11 mm in height and 6 mm in the antero-posterior dimension. It was the largest pneumatocyst we have recorded in the last 5 years. The radiographic presentation of the entity was concerning for a possible malignant neoplasm. A second opinion was requested from a neuroradiologist from the university hospital, who confirmed that it was consistent with a pneumatocyst. The air density of the lesion was a key feature that helped in the diagnosis. <h3>DISCUSSION/CONCLUSIONS</h3> The pathophysiology of pneumatocysts is not clear, but it is believed to be related to gas accumulation from the vertebral spaces that extends into the vertebral body. The lesions do not cause any symptoms and are discovered usually as an incidental finding. There are very few case reports of pneumatocyst in the spine in the literature. These lesions can enlarge with time and become fluid-filled and eventually contain granulation tissue. In 2D radiographs they have been mistaken for other aggressive lesions like multiple myeloma and metastases. It is therefore important to have an understanding of the presentation of these entities in CBCT scans. The air density and regular borders are key imaging features that help in the diagnosis.