ABSTRACT
Fibrocartilaginous mesenchymoma (FM) is a rare bone tumor mimicking other fibrocartilaginous lesions on imaging and histologically. Hence, it is difficult to diagnose this entity especially on small biopsies. In this article, we report a case of FM mimicking desmoplastic fibroma on biopsy. A 36-year-old male presented with pain in the left hip. Imaging showed a large expansile lytic lesion involving the acetabulum and pubis. The differential diagnosis was suggestive of giant cell tumor, aneurysmal bone cyst, intraosseous desmoplastic fibroma, and chondrosarcoma. Biopsy revealed a low-grade spindle cell lesion with no evidence of osteoid or chondroid matrix. The lack of cartilaginous nodules in the biopsy prompted a preoperative diagnosis of desmoplastic fibroma. The excised mass showed bland spindle cell proliferation, benign cartilage nodules, and epiphyseal plate-like enchondral ossification suggestive of fibrocartilaginous mesenchymoma. Negative immunostaining for SATB2, CDK4, and MDM2 ruled out low-grade central osteosarcoma. Though GNAS mutations were not performed in this case, rimming of the bony trabeculae at the periphery of the epiphyseal growth plate-like cartilaginous nodule ruled out fibrous dysplasia. The absence of cartilaginous component misleads the diagnosis preoperatively in small biopsies.
Subject(s)
Bone Neoplasms , Fibroma, Desmoplastic , Mesenchymoma , Male , Humans , Adult , Mesenchymoma/diagnostic imaging , Mesenchymoma/surgery , Bone Neoplasms/diagnostic imaging , Bone Neoplasms/surgery , Bone and Bones/pathology , Pelvis/pathologyABSTRACT
Fibrocartilaginous mesenchymoma is a rare bone tumor, with fewer than 35 cases reported in the literature since 1984. This tumor usually occurs in the long bones of children and adolescents. In the current case, the tumor affected a rib. A 17-year-old boy presented with a mass in the right fifth rib. Radiologic findings revealed an osteolytic mass with cortical destruction and calcification; en bloc resection was performed. The tumor showed three distinct histologic features: bland spindle cell proliferation, benign cartilage nodules, and epiphyseal plate-like enchondral ossification. The pathologic diagnosis was fibrocartilaginous mesenchymoma. The patient remains free of disease 1 year after the surgery. Pathological diagnosis of fibrocartilaginous mesenchymoma can be challenging, especially when the tumor occurs in an unusual site. When any fibro-osseous lesion with a cartilaginous component is encountered, the possibility of fibrocartilaginous mesenchymoma should be considered because of its locally aggressive behavior.
ABSTRACT
AIMS: Fibrocartilaginous mesenchymoma is a rare intraosseous lesion, with a total of 26 cases described in the literature. This study describes the clinical, radiological and histological features of eight new cases of fibrocartilaginous mesenchymoma collected at a single institution between 1982 and 2016. The presence of GNAS and IDH1/2 mutations and MDM2 amplification was explored to evaluate possible links between fibrocartilaginous mesenchymoma, fibrous dysplasia, de-differentiated chondrosarcoma and low-grade osteosarcoma. METHODS AND RESULTS: Eight new cases of fibrocartilaginous mesenchymoma of bone identified in our archives, dating from 1982 to 2016, were reviewed. The diagnosis was not performed on the initial biopsy in any of these cases, due mainly to the absence of obvious cartilaginous differentiation. On imaging, the tumour contained cartilaginous calcifications and showed a very strong uptake of contrast medium after injection. Histologically, the tumour was characterized by spindle cell proliferation mimicking a low-grade spindle cell sarcoma, associated with epiphyseal growth-plate-like nodules of cartilage and bone production. Molecularly, no GNAS and IDH1/2 mutations or MDM2 amplification were found in the cases analysed. Only one case recurred 1 year following intralesional resection. None died of disease. CONCLUSIONS: This very rare bone tumour has a typical radiological and histological pattern and a favourable survival outcome after treatment. Local recurrences can be prevented with complete surgery. Fibrocartilaginous mesenchymoma does not seem to be related genetically to fibrous dysplasia, low-grade osteosarcoma and de-differentiated chondrosarcoma.
Subject(s)
Bone Neoplasms/pathology , Mesenchymoma/pathology , Adolescent , Adult , Bone Neoplasms/diagnosis , Bone Neoplasms/genetics , Child , Child, Preschool , Female , Humans , Infant , Male , Mesenchymoma/diagnosis , Mesenchymoma/genetics , Young AdultABSTRACT
El mesenquimoma fibrocartilaginoso (MFC) es un tumor raro, que afecta principalmente a los huesos largos. Se han reportado pocos casos desde su descripción. Presentamos un caso de un niño de 4 años de edad con MFC situado en el húmero. Las radiografías mostraron una lesión lítica expansiva situada en la región metafisaria del húmero proximal. La resonancia magnética objetivó expansión del tumor a partes blandas. La anatomía patológica fue confirmatoria de MFC. El paciente fue tratado con curetaje, fenolización adyuvante y sustituto óseo mezclado con aspirado de médula ósea. A los dos años de seguimiento, no se evidenció recidiva. El MFC debe ser tenido en cuenta entre los diagnósticos diferenciales en lesiones óseas líticas en niños y adolescentes.
Fibrocartilaginous mesenchymoma (FCM) is a rare tumor that primarily affects the long bones. Few cases have been reported since its description. A case of a 4-year-old boy with FCM located in the humerus is presented. Radiological examination showed an expansive lytic lesion located in the metaphyseal proximal humerus. Magnetic resonance imaging showed soft tissue expansion. Histopathological diagnosis was confirmatory of FCM. Curettage, adjuvant phenolization, and bone grafting with bone substitute, and autologous bone marrow was performed. During a follow-up period of 2 years, there was no evidence of disease progression. FCM should be considered in the differential diagnosis of lytic bone lesions in children and adolescents.
Subject(s)
Child, Preschool , Humans , Male , Bone Neoplasms/pathology , Humerus , Mesenchymoma/pathology , FibrocartilageABSTRACT
El mesenquimoma fibrocartilaginoso (MFC) es un tumor raro, que afecta principalmente a los huesos largos. Se han reportado pocos casos desde su descripción. Presentamos un caso de un niño de 4 años de edad con MFC situado en el húmero. Las radiografías mostraron una lesión lítica expansiva situada en la región metafisaria del húmero proximal. La resonancia magnética objetivó expansión del tumor a partes blandas. La anatomía patológica fue confirmatoria de MFC. El paciente fue tratado con curetaje, fenolización adyuvante y sustituto óseo mezclado con aspirado de médula ósea. A los dos años de seguimiento, no se evidenció recidiva. El MFC debe ser tenido en cuenta entre los diagnósticos diferenciales en lesiones óseas líticas en niños y adolescentes.(AU)
Fibrocartilaginous mesenchymoma (FCM) is a rare tumor that primarily affects the long bones. Few cases have been reported since its description. A case of a 4-year-old boy with FCM located in the humerus is presented. Radiological examination showed an expansive lytic lesion located in the metaphyseal proximal humerus. Magnetic resonance imaging showed soft tissue expansion. Histopathological diagnosis was confirmatory of FCM. Curettage, adjuvant phenolization, and bone grafting with bone substitute, and autologous bone marrow was performed. During a follow-up period of 2 years, there was no evidence of disease progression. FCM should be considered in the differential diagnosis of lytic bone lesions in children and adolescents.(AU)