Vertebral Pneumatocysts: Uncommon Lesions with Pathognomonic Imaging Characteristics

This article reviews the typical imaging characteristics of a vertebral pneumatocyst, an unusual, intraosseous gas-containing lesion of uncertain etiology. Pneumatocysts are usually found within the ilium or sacrum, adjacent to the sacroiliac joints. Fewer than 12 case reports of pneumatocysts of the spine were identified in the English-language literature; in eight of these cases, the lesions were present within the cervical spine (1–7). However, pneumatocysts are probably more common than has been reported. Vertebral body pneumatocysts are benign lesions that need to be differentiated from other gas-containing lesions of the spine, including those caused by osteomyelitis, osteonecrosis, and neoplasm as well as posttraumatic and postsurgical causes. The etiology and natural course of pneumatocysts are poorly understood, although the diagnosis can be reliably determined through a combination of computed tomography (CT) and magnetic resonance (MR) imaging characteristics alone, as shown in the five case studies below.