Rita Indirli1, Carmelo Messina2, Matteo Longhi3, Gregorio Guabello3, Sabrina Corbetta4. 1. Department of Clinical Sciences and Community Health, University of Milan, Milan, MI, Italy; Endocrinology Unit, Fondazione IRCCS Ca'Granda Ospedale Maggiore Policlinico, Milan, MI, Italy. 2. Department of Biomedical Sciences for Health, University of Milan, Milan, MI, Italy; Radiology Unit, IRCCS Istituto Ortopedico Galeazzi, Milan, MI, Italy. 3. Rheumatology Unit, IRCCS Istituto Ortopedico Galeazzi, Milan, MI, Italy. 4. Department of Biomedical, Surgical and Dental Sciences, University of Milan, Milan, MI, Italy; Endocrinology and Diabetology Service, IRCCS Istituto Ortopedico Galeazzi, Milan, MI, Italy. Electronic address: sabrina.corbetta@unimi.it.
Abstract
BACKGROUND: Melorheostosis is a rare sporadic sclerosing bone dysplasia, which commonly affects appendicular skeleton with bone hyperostosis and soft tissues sclerosis; fragility fractures are rare in melorheostotic patients. We investigated bone features at unaffected sites in a postmenopausal woman with melorheostosis of the right lower limb and with a fracture of the melorheostosis-free T11 vertebral. METHODOLOGY: Melorheostotic lesions were evaluated by plain radiography, magnetic resonance of the right lower limb, and whole-body bone scintigraphy. Dual X-ray absorptiometry, trabecular bone score, and quantitative computed tomography were performed to investigate unaffected bone sites. Biochemical assessment of bone metabolism was obtained. RESULTS: Dual X-ray absorptiometry was indicative of normal mineralization at femoral sites and osteopenia at lumbar spine (T-score -1.1), which was confirmed by spinal quantitative computed tomography (volumetric bone mineral density 89 mg/cm3). Trabecular bone score suggested only mildly altered bone microarchitecture (1.304, normal values >1.350). Bone markers were consistent with high bone turnover. Causes of secondary osteoporosis or alterations in bone metabolism were excluded. Zoledronic acid induced a reduction in bone turnover markers after 6 months without significant changes in clinical features. CONCLUSIONS: Fragility fractures at apparently unaffected sites may occur in adults with melorheostosis, in absence of significant demineralization diagnosed by dual X-ray absorptiometry, trabecular bone score, and quantitative computed tomography, which may underestimate the fracture risk in this set of patients. Treatment with zoledronate could be considered also to prevent fragility fractures.
BACKGROUND:Melorheostosis is a rare sporadic sclerosing bone dysplasia, which commonly affects appendicular skeleton with bone hyperostosis and soft tissues sclerosis; fragility fractures are rare in melorheostotic patients. We investigated bone features at unaffected sites in a postmenopausal woman with melorheostosis of the right lower limb and with a fracture of the melorheostosis-free T11 vertebral. METHODOLOGY:Melorheostotic lesions were evaluated by plain radiography, magnetic resonance of the right lower limb, and whole-body bone scintigraphy. Dual X-ray absorptiometry, trabecular bone score, and quantitative computed tomography were performed to investigate unaffected bone sites. Biochemical assessment of bone metabolism was obtained. RESULTS: Dual X-ray absorptiometry was indicative of normal mineralization at femoral sites and osteopenia at lumbar spine (T-score -1.1), which was confirmed by spinal quantitative computed tomography (volumetric bone mineral density 89 mg/cm3). Trabecular bone score suggested only mildly altered bone microarchitecture (1.304, normal values >1.350). Bone markers were consistent with high bone turnover. Causes of secondary osteoporosis or alterations in bone metabolism were excluded. Zoledronic acid induced a reduction in bone turnover markers after 6 months without significant changes in clinical features. CONCLUSIONS:Fragility fractures at apparently unaffected sites may occur in adults with melorheostosis, in absence of significant demineralization diagnosed by dual X-ray absorptiometry, trabecular bone score, and quantitative computed tomography, which may underestimate the fracture risk in this set of patients. Treatment with zoledronate could be considered also to prevent fragility fractures.