CT and MRI of fibrous dysplasia of the spine

Abstract

Objectives: The purpose of this study was to present the CT and MRI findings of patients with fibrous dysplasia (FD) of the spine. Methods: Among the patients with pathologically proven skeletal FD, 12 (8 males and 4 females; mean age, 43 years) who were evaluated with either spine CT or MRI were included. The number and location of the involved vertebral segments, the presence of lytic lesions, ground-glass opacity (GGO), an expansile nature, cortical disruption, a sclerotic rim, a decrease in body height and contour deformity were examined on CT scans (n512), while signal intensity, enhancement patterns and the presence of a dark signal rim on the lesion were examined using MRI (n59). Results: Nine patients had polyostotic FD, including one with an isolated spinal localisation, while three had monostotic FD. An expansile nature (n53) and osteolytic lesions with GGO (n53) were seen. On CT images, GGO was noted in all patients. An expansile nature (n511) and presence of lytic lesions (n511) were noted. A decrease in body height (n59) and sclerotic rim formation (n59) were indicated. Contour deformities were visible in six patients. The MRI findings were non-specific. Dark signal rims were visible on MRI in seven patients. Conclusion: Typical imaging findings of extraspinal FD were noted on spine CT scans. These characteristic CT imaging findings of spinal FD may be helpful in differentiating FD from other common spine diseases. Fibrous dysplasia (FD) is a developmental defect of osteoblastic differentiation and bone maturation of unknown origin [1]. FD may affect the skeleton either in isolation (monostotic FD, rate, 70-80%; and polyostotic FD, rate, 20-30%) or in variable combination with endocrine and cutaneous abnormalities (McCune-Albright syndrome) [2][3][4][5]. Although patients afflicted with FD may present at any age, they are typically young and in the first and second decades of life [6]. After puberty, dysplastic areas rarely expand [7]. In general, the progression of the skeletal lesions tends to be exhausted once patients have reached adult age [7]. The diagnosis of FD is difficult in adult patients because cases in older patients, especially those involving the spine, are rare.FD represents approximately 7% of all benign tumourlike bone lesions [8]. However, the spine is affected in only 2.5% of cases, and FD of the spine is very rarely observed without there being disease elsewhere in the body [9]. Spinal involvement occurs mostly in the polyostotic form of FD; it is unusual for it to occur in the monostotic form [9,10]. When present in the elderly with multiple vertebral lesions, a biopsy may be indicated because metastatic disease or multiple myeloma may simulate a benign non-aggressive process. Therefore, active diagnosis and radiological familiarity of spinal FD are thought to be essential for preventing unnecessary examinations or procedures.The purpose of this study was to present the CT and MRI findings of spinal FD, which is rare, and to assess the efficacy of CT in the diagnosis of FD. Me...

Isolated polyostotic fibrous dysplasia of the spine: A diagnostic challenge

“…Fibrous dysplasia affecting the vertebrae is very unusual [1,3,4,7,8]. Dahlin and Unni found only two cases of vertebral involvement out of 418 cases reviewed [3].…”

“…Lumbar spine has been found to be involved in majority of case [4,11] followed by cervical and thoracic spine [5,7,9,10,12].…”

“…Polyostotic form of the disease occurs more frequently than the monostotic form and usually involves bones of the pelvis, femur, tibia, ribs, calvarium and the facial bones. Vertebral involvement in both types is extremely uncommon [1][2][3][4][5]. In a typical case of polyostotic disease involving multiple bones of the axial skeleton with or without clinical stigmata of the disease, the presence of disease in a single or multiple vertebrae may not pose a diagnostic problem.…”

A 33-year-old Man With Low Back Pain

“…Radiographic findings of fibrous dysplasia of the spine were reviewed in detail by Park et al [29]. Radiographically, fibrous dysplasia of the spine shows a lytic and expansile lesion, with thinning of the cortical bone in a scalloped, undulating pattern owing to endosteal erosion, but without cortical disruption.…”

“…MRI usually exhibits a dark signal rim consistent with peripheral bony sclerosis. Although decreased signal intensities may be expected on MRI because of the presence of fibrous tissues, signal intensities on T1-weighted and T2-weighted MR images have been shown to be nonspecific in fibrous dysplasia [29].…”