Fibrous Dysplasia of the Spine—A Case Involving the Polyostotic Form Isolated to the Thoracolumbar Spine

ABSTRACT

Fibrous dysplasia of the spine in a polyostotic form is very rare, with fewer than 36 cases discussed in the literature and there is no such case in Indonesia that has been reported. The aim of this report is to present a case from Indonesia of polyostotic fibrous dysplasia isolated in the spine. We report a case of a 38-year-old Sundanese man with a 1-year history of progressive back pain and weakness of both lower extremities. There was no history leading to infection and no previous trauma. A physical examination revealed kyphoscoliotic deformity, a café au lait spot, tenderness at the thoracolumbar region, and neurological deficits. Laboratory studies were within normal ranges. Plain radiographs showed lytic lesion and kyphoscoliosis. Magnetic resonance imaging showed an endosteal scalloping, infiltrative process, expansion, and destruction in the vertebral bodies from T2 to L5. The findings of an aggressive destructive process was highly suspicious of a malignant process, relying on differential diagnosis and metastases, plasma cell myeloma, bone tumor and chronic infectious spondylitis. Histology revealed an irregularly oriented osteoid without osteoblastic rimming but surrounded by fibroblastic proliferation with a C-shaped sign. Investigations revealed a diagnosis of polyostotic fibrous dysplasia of the thoracolumbar spine in isolation. The patient underwent T5-S1 stabilization and bone grafting. At 1 year postoperative, the patient was asymptomatic; there was no recurrence and minimal neurological deficit with grade II on the modified McCormick scale. A case of the polyostotic form of fibrous dysplasia of the spine in isolation has never been reported in Indonesia. The extreme rarity of this type of presentation can pose a diagnostic dilemma, and in cases isolated to the spine, surgical treatment with posterior stabilization, decompression, and bone grafting gives a good functional outcome.