Monostotic fibrous dysplasia of a lumbar vertebral body with secondary aneurysmal bone cyst formation: a case report

Abstract

We report the case of a 25-year-old Caucasian woman with symptomatic monostotic fibrous dysplasia of the fourth lumbar vertebral body. The patient suffered from a five-week history of progressive low back pain, radiating continuously to the left leg. Her medical history and physical and neurological examination did not demonstrate any significant abnormalities. Radiographs, computed tomography and magnetic resonance imaging revealed an osteolytic expansive lesion with a cystic component of the fourth lumbar vertebral body. Percutaneous transpedicular biopsy showed histological characteristics of fibrous dysplasia superimposed by the formation of aneurysmal bone cyst components. The patient was treated by subtotal vertebrectomy of the L4 vertebral body with anterior reconstruction and her postoperative course was uncomplicated. To our knowledge, this is the first reported case of a monostotic fibrous dysplasia with superimposed secondary aneurysmal bone cysts of a lumbar vertebral body.

Figure 1

Left oblique radiograph of the lumbar spine demonstrating radiolucency of vertebra L4.

Figure 2

Transversal CT image of the L4 vertebral body, demonstrating remodelling in partially sclerotic bone.

Figure 3

Sagittal T2-weighted MRI demonstrating cystic components of vertebra L4.

Figure 4

Whole-body bone scintigraphy with 99mTc-HDP showing an intense, local enhanced uptake at level L4 with areas of decreased uptake demonstrating the cystic components.

Figure 5

HE-stained (5 x objective) decalcified percutaneous transpedicular biopsy showing on the left side aneurysmatic structures (*), and on the right side margins of fibrous dysplasia (O) infringing on laminar bone structures.

Figure 6

Postoperative AP and lateral radiograph demonstrating the subtotal vertebrectomy of the L4 vertebral body and anterior reconstruction of the defect with the use of an anterior stackable cage and anterior instrumentation.