RESUMO
A diagnosis of clear cell chondrosarcoma of the ulna was made in a patient with Von Hippel-Lindau disease (VHL). After surgery, genetic analysis of the tumor tissue showed loss of heterozygosity at the VHL gene locus. Immunohistochemical analysis confirmed loss of expression of the VHL protein in the tumor cells. In addition, abundant Cyclin D1 expression in the tumor was observed. Chondrosarcoma has been described before in a VHL patient and VHL protein expression has been correlated to tumor grade in a series of sporadic chondrosarcomas. In this report, we show that clear cell chondrosarcoma may be a rare but canonical VHL manifestation through a cell-autonomous mechanism involving somatic loss-of-heterozygosity of the VHL tumor suppressor gene. We discuss the relevance of this observation with regard to the pathogenesis of clear cell chondrosarcoma in the context of VHL.
Assuntos
Neoplasias Ósseas/genética , Condrossarcoma de Células Claras/genética , Perda de Heterozigosidade , Ulna , Proteína Supressora de Tumor Von Hippel-Lindau/genética , Doença de von Hippel-Lindau/genética , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/cirurgia , Condrossarcoma de Células Claras/diagnóstico por imagem , Condrossarcoma de Células Claras/metabolismo , Condrossarcoma de Células Claras/cirurgia , Ciclina D1/metabolismo , Feminino , Humanos , Pessoa de Meia-Idade , Doença de von Hippel-Lindau/complicaçõesRESUMO
Clear cell chondrosarcoma (CCCS) is a rare variant of conventional chondrosarcoma with low-grade malignant features that may be confused radiographically and histologically with chondroblastoma. We report a case of a 50-year-old female who presented with 6 months of left hip pain. Initial radiographs demonstrated an osteolytic lesion with adjacent area of sclerosis in the proximal left femur. Magnetic resonance imaging demonstrated a marrow-infiltrative lesion with periosteal reaction and thickened enhancing periosteum. Biopsy of the sclerotic area demonstrated chondroblastoma-like findings, whereas biopsy of the lytic area showed features suggestive of CCCS. The patient eventually underwent en bloc resection and reconstruction with a proximal femoral megaprosthesis. The final diagnosis was CCCS. We present this unusual case with review of the radiographic and histologic features of CCCS with attention to its ability to mimic chondroblastomas. This case highlights the importance of sampling radiographically heterogeneous areas within a bone lesion to facilitate accurate diagnosis and appropriate management.
