Case report 769. Fibrous dysplasia

Keep your eyes on the ribs: the spectrum of normal variants and diseases that involve the ribs

A variety of normal variants or pathologic conditions of the ribs may be overlooked at chest radiography if the ribs are not evaluated carefully. Rib lesions may simulate pulmonary disease as well. Normal rib variants include cervical, intrathoracic, and pelvic ribs; forked rib; fusion and bridging; and pseudarthrosis of the first rib. Trauma-related lesions are common and usually occur in isolation but can alert the radiologist to other injuries. Metastases may appear as vague areas of increased opacity overlying the lung if seen en face and typically have a smooth interface with the lung on oblique images. Chondroid lesions nearly always arise at or near the anterior end of the rib. Osteochondroma (exostosis) typically manifests as a deformity or expansion of the rib with calcification of the cartilaginous cap. Acute rib infections are seen as focal areas of bone destruction, whereas chronic infections may manifest as periosteal reaction or a bone sequestrum. Inferior rib notching may be seen in a wide variety of pathologic conditions. Rib abnormalities may also be seen in fibrous dysplasia, Langerhans cell histiocytosis, Paget disease, and various hemoglobinopathies. In most cases, radiography is sufficient for the identification and diagnosis of normal variants and pathologic conditions of the ribs.

Long-term effects of intravenous pamidronate in fibrous dysplasia of bone

Fibrous dysplasia of bone (FD) is a rare disorder characterized by proliferation of fibrous tissue in bone marrow leading to osteolytic lesions. It causes bone pain and fractures. To date the only treatment is orthopedic. Histological and biochemical similarities between FD and Paget's bone disease related to increased osteoclastic resorption led us to propose treatment with the bisphosphonate pamidronate. The aim of the study was to assess the long-term effects of intravenous pamidronate in FD. In this open label phase III study, 20 patients with FD (11 males and 9 females; mean age 31 years) received courses of 180 mg of intravenous pamidronate every 6 months (60 mg/day during 3 days by infusion). The mean duration of follow-up was 39 months (range 18-64). Severity of bone pain, number of painful skeletal sites per patient, X-rays of all involved areas, serum alkaline phosphatase, fasting urinary hydroxyproline, and urinary type I collagen C-telopeptide were assessed every 6 months. The severity of bone pain and the number of painful sites appeared to be significantly reduced. All biochemical markers of bone remodeling were substantially lowered. We observed a radiographic response in nine patients with refilling of osteolytic lesions. A mineralization defect proven by bone biopsy was observed in one case. Four patients sustained bone stress lines, but no fracture occurred. We suggest that intravenous pamidronate alleviates bone pain, reduces the rate of bone turnover assessed by biochemical markers, and improves radiological lesions of FD. Few side effects were observed.