Oral Alendronate Treatment for Severe Polyostotic Fibrous Dysplasia due to McCune-Albright Syndrome in a Child: A Case Report

McCune-Albright Syndrome (MAS) is a rare disease presenting with the classical triad of polyostotic fibrous dysplasia (FD), skin hyperpigmentation (café-au-lait spots) and endocrine dysfunction, usually seen as precocious puberty in females. The mosaicism of mutations in the GNAS1 gene results in hyperactive Gsα protein which causes activation of hormonal receptors and bone dysplasia [1–3]. There is increased osteoclastic activity, which can be detected by the elevation of biochemical markers of bone turnover, and normal bone marrow architecture is progressively replaced by abnormal fibrous tissue [4, 5].bisphosphonates, antiresorption agents, largely used in the treatment of osteoporosis have been tried as an option for improvement of FD symptoms in MAS [6–9]. Most patients are treated with intravenous pamidronate, in a hospital regimen, or as outpatients in clinic settings. Alendronate (ALN) is a second-generation bisphosphonate that has, as an advantage, oral administration. It has been used for treatment of several disorders related to increased bone resorption; however, it is rarely used by the pediatric population.Since we could not find reports on the use of oral ALN in children with FD of MAS, although we are aware of an ongoing, as yet unpublished, study with children [4], we present the case of a girl with MAS treated during a one-year period with oral ALN.A 10.5-year-old white girl was admitted with complaints of severe weekly headache, diplopia, and nasal obstruction. She also had daily bone leg pains which caused frequent school absenteeism. She was in outpatient followup since she was 20 months old when it was noticed café-au-lait spots. By the age of 3 years she presented with left exophthalmos, and a severe form of FD of skull, which leads to the diagnosis of MAS. She had already undergone left optical nerve surgical decompression at 5 years of age and a second procedure was under consideration. At 6 and 10 years of age she was submitted to two turbi