RESUMEN
Clinical, histological, and genetic studies of two cases of isolated fibro-osseous lesions of the femur in adults show the overlap between monostotic fibrous dysplasia (MFD) of the proximal femur and the so-called liposclerosing myxofibrous tumor. The two cases highlight how the incomplete understanding of the natural history of MFD may result in diagnostic pitfalls or incorrect classification of individual lesions.
Asunto(s)
Neoplasias Femorales/patología , Fibroma/patología , Displasia Fibrosa Monostótica/patología , Adulto , Cromograninas , Diagnóstico Diferencial , Femenino , Neoplasias Femorales/clasificación , Neoplasias Femorales/genética , Neoplasias Femorales/cirugía , Cuello Femoral/patología , Cuello Femoral/cirugía , Fibroma/clasificación , Fibroma/genética , Fibroma/cirugía , Displasia Fibrosa Monostótica/clasificación , Displasia Fibrosa Monostótica/genética , Displasia Fibrosa Monostótica/cirugía , Subunidades alfa de la Proteína de Unión al GTP Gs/genética , Humanos , Persona de Mediana Edad , Mutación , Polimorfismo de Longitud del Fragmento de Restricción , EsclerosisRESUMEN
In this paper, the etiology of monostotic fibrous dysplasia and McCune-Albright syndrome is explained. Both monostotic fibrous dysplasia and McCune-Albright syndrome are sporadically occurring disorders in which a mutation in the GNAS1 gene occurs postzygotically in a somatic cell. All cells descended from the mutated cell can manifest features of McCune-Albright syndrome or fibrous dysplasia. Cells descended from non-mutated cells develop into normal tissues. Thus, the clinical pattern is variable in distribution and appearance. More generalized vs more localized expression depend on (a) how small or how large the cell mass is during embryogenesis when the mutation occurs and (b) where in the cell mass the mutation occurs. Topics discussed include G proteins and their receptors, cycling of stimulatory G protein between active and inactive forms, and specific mutations in GNAS1. We also discuss four possibilities: (a) Are there masked mutations? (b) Are there effects of imprinting? (c) Are there non-classical mutations? and (d) Is fibrous dysplasia a neoplasm?
Asunto(s)
Displasia Fibrosa Monostótica/etiología , Displasia Fibrosa Poliostótica/etiología , Displasia Fibrosa Monostótica/clasificación , Displasia Fibrosa Monostótica/genética , Displasia Fibrosa Monostótica/metabolismo , Displasia Fibrosa Poliostótica/genética , Displasia Fibrosa Poliostótica/metabolismo , Subunidades alfa de la Proteína de Unión al GTP Gs/genética , Subunidades alfa de la Proteína de Unión al GTP Gs/metabolismo , Impresión Genómica/genética , Humanos , Mutación/genética , Terminología como AsuntoRESUMEN
AIM: To report a case of focal cemento-osseous dysplasia (FCOD) affecting a single tooth misdiagnosed as an inflammatory periapical lesion. SUMMARY: The patient, a black 47-year-old woman complained of pain affecting the right side of the mandible. Routine X-ray examination discovered a periapical radiolucency on the mandibular left lateral incisor (tooth 32), which was otherwise normal and not carious. As the response of this tooth to a vitality test was doubtful, the lesion was diagnosed as a periapical granuloma or cyst secondary to pulpal necrosis. Endodontic treatment and curettage of the periapical lesion were performed, and histological examination of the curettage material revealed a localized osseous dysplasia. KEY LEARNING POINTS: FCOD may rarely affect only one tooth, resembling a periapical granuloma or cyst. Careful diagnosis is of paramount importance in cases of questionable periapical lesions affecting normal-looking teeth, before beginning treatment. FCOD generally requires no treatment. Biopsy is warranted in case of doubt.