Low-Grade Myofibroblastic Sarcoma Of The Bone

摘要

Myofibroblastic tumours are soft tissue neoplasms arising in myofibroblasts, ubiquitous cells sharing ultrastructural features of muscular and fibroblastic cells. A malignant counterpart of the well-described myofibroblastic benign tumours was described by Vasudev and Harris in 1978, but was not fully characterized as a separate entity until recently. Most reported cases of this rare neoplasm have arisen in the head and neck area, although some cases affecting the soft tissues of the extremities have been reported. To our knowledge, there have only been 7 reports on primary myofibroblastic sarcoma/myofibrosarcoma of the bone, two of them affecting the jaws. We herein report a new case of this rare tumour affecting the right femur of a 24 year-old black African man and comment briefly on the confusing terminology regarding these lesions. Introduction Myofibroblasts are spindle mesenchymal cells sharing features of both muscular and fibroblastic cells.[1] They are important for wound healing and are considered the main cell originating some benign neoplasms, like myofibroblastoma [2] or angiomyofibroblastoma. Although in 1978 Vasudev and Harris described for the first time a sarcoma with ultrastructural features of myofibroblasts [3], the malignant neoplasm originating in these cells (myofibroblastic sarcoma) was not fully characterized until 1998,[4] when Mentzel et al. reported 18 cases arising in different locations and set forth criteria for diagnosis. Myofibroblastic sarcomas/myofibrosarcomas of the bone seem to be extremely rare and after a thorough Medline Search we have only 7 cases reported under these names in the world literature.[5,6] Case Report A 24-year-old black man born in Guinea consulted in March, 2001 on a huge mass in his right popliteal fossa. He had first noticed the mass three months before and he referred a rapid growth. He had no associated systemic symptoms and only referred pain and functional disability in the affected leg. His past medical history was irrelevant. The plain radiograph of the right leg showed a lytic mass in the distal third of the femur with focal destruction of the cortical of bone and soft-tissue extension (Fig. 1).