A unique case of multiple non-ossifying fibromas with polyostotic monomelic distribution and aggressive clinical course

Abstract

Multiple non-ossifying fibromas (MNOFs) occur either isolated or in association with other anomalies, are usually localized in the long bones of the lower limbs, may be radiographically confused with other skeletal lesions, and tend to heal spontaneously with the completion of the skeletal growth. Segmental distribution, either monomelic or polymelic and ipsilateral, is rare and commonly observed in the context of developmental diseases known as "RASopathies", which are caused by mutations in genes that encode components or regulators within the Ras/mitogen-activated protein kinase signaling pathway. We describe here the radiographic and pathologic features of an 18-year-old Caucasian boy, whose clinical history started at the age of 3 when the diagnosis of aneurysmal bone cyst was made on a lytic lesion of his left clavicle. Over the following 2 years, the patient developed polyostotic and monomelic lesions within the left humerus, radius, and ulna. No other skeletal and extra-skeletal anomalies were clinically detected. The lesions were interpreted as consistent with polyostotic fibrous dysplasia and MNOFs and showed an unusually aggressive clinical course with progressive increase in size and coalescence. The definitive diagnosis of MNOFs was made after the exclusion of fibrous dysplasia by molecular analysis. The polyostotic and monomelic distribution of the lesions and the unusually aggressive clinical course contribute to make this case of MNOFs unique.

Bisphosphonate-induced zebra lines in fibrous dysplasia of bone: histo-radiographic correlation in a case of McCune–Albright syndrome

“…After fixation, they were either routinely processed for paraffin embedding after decalcification (4% EDTA in phosphate buffer, pH 7.0) or processed undecalcified for methyl-methacrylate (MMA) embedding as described previously [8, 29]. The diagnosis of FD of bone was repeatedly confirmed by histology and also by molecular analysis that was performed on genomic DNA extracted from fresh or paraffin embedded tissue as described previously [29, 35, 36] and demonstrated R201C mutation of exon 8 of the GNAS gene (data not shown). Two of the bone samples were obtained at the time of the valgus osteotomy of the proximal femur and varus osteotomy of the proximal tibia (Fig.…”

An unusually aggressive multiple non-ossifying fibroma of the distal tibia and fibula: A case report

“…Multiple non-ossifying fibromas (MNOFs) are not uncommon representing less than 5 % of all NOF ( Emori et al, 2022 ). They may be isolated and usually symmetrical, or in association with other skeletal and extra-skeletal abnormalities forming the group of syndromic MNOFs ( Corsi et al, 2017 ; Dorfman and Czerniak, 1999 ). Syndromic MNOFs are often asymmetrical and are seen in association of diverse developmental syndromes, such as type I neurofibromatosis and Jaffé-Campanacci syndrome ( Corsi et al, 2017 ).…”