Vol 1 | Issue 1 | May – August\u00a02015 | page:23-28 | Yogesh Panchwagh[1*].<\/p>\n
[1]Orthopaedic Oncology Clinic, Pune, India.<\/p>\n
Address of Correspondence<\/strong> Ewing sarcoma is one of the common primary bone sarcomas affecting patients mostly in the second decade. Appropriate clinical examination, investigations, staging, biopsy and multi-modal treatment are essential for good outcome. Neo-adjuvant and adjuvant chemotherapy have shown definite benefits in local and systemic control and in improving survival. Though historically, emphasis of treatment was on radiation, non metastatic Ewing sarcoma is shown to have better outcome with surgical excision as compared to definitive radiotherapy. Limb salvage surgery is currently the norm given the excellent functional outcomes. Various reconstruction options are available depending upon the age, site and size of the lesion. Appropriate follow up is essential to pick up local and systemic failures early. Individualized approach may be required for patients who are metastatic at presentation. Ewing Sarcoma (ES) is a highly aggressive malignant tumor affecting mostly the immature skeleton, more commonly in the second decade of life. ES is named after Dr. James Ewing, a pathologist. Its aetiopathogenesis has evolved from \u201cEndothelioma of bone\u201d to a unique malignant tumor of bone with well described translocation t(11;22)(q24;q12) as a possible causative factor [1]. The classical pathology of small round blue cells makes it a part of the Round cell family of tumors, the other members of which are rhabdomyosarcoma, synovial sarcoma, non-Hodgkin’s lymphoma, retinoblastoma, neuroblastoma, hepatoblastoma, and nephroblastoma or Wilms’ tumor [2].<\/p>\n Clinical presentation<\/span><\/strong> <\/a> Staging<\/span><\/strong> Biopsy<\/span><\/strong>
\nDr. Yogesh Panchwagh.
\nOrthopaedic Oncology Clinic, 101, Vasant plot 29, Bharat Kunj Society -2, Erandwana, Pune – 38, India.
\nEmail: drpanchwagh@gmail.com<\/p>\n
\nAbstract<\/span><\/strong><\/h3>\n
\nKeywords:<\/strong> Ewing sarcoma, Surgery, Limb salvage, reconstruction.<\/p>\n
\nIntroduction<\/span><\/strong><\/h3>\n
\nA high index of suspicion is required to diagnose a primary bony sarcoma like ES at a very early stage. The patients, typically in their first two decades of life, usually have a history of 2-6 months duration, of a painful, progressively increasing swelling in the affected area. Most of the patients give a concomitant history of trauma, which is coincidental. Some of the patients may have a history of fever [3,4].
\nClinical examination reveals a tender diffuse swelling in the affected area. The range of motion of the adjoining joint may be terminally restricted. The palpation may reveal local warmth. Though the most commonly affected site is the diaphysis in the bone, ES is known to affect the metaphyseal region as well [3]. ES may affect any bone in the body (Fig 1 a-e). Periosteal ES located on the surface of bone and soft tissue ES, though rare, are well-defined clinical entities [3].
\n\u2018The clinical and radiological features in an ES of bone may be akin to osteomyelitis or an eosinophilic granuloma and these differentials have to be borne in mind and ruled out by subsequent investigations.<\/p>\n
\nWork up:
\nThe work up includes plain radiographs of the affected bone including the nearby joint, M.R.I. scan of the involved bone, and either a PET CT [7,8,9] or a CT Chest with Technetium Bone scan and a bone marrow aspiration biopsy [3]. The x ray ( Figure 1, a-e) usually shows a permeative, lytic lesion with lamellated periosteal reaction. In locally advance cases, an extra osseous soft tissue component is common [1,3,5]. A diaphyseal lesion may exhibit a characteristic \u201cOnion peel\u201d periosteal reaction. In some cases, \u201chair-on-end\u201d or \u201csun-ray spicule\u201d type of periosteal reaction may also be seen.
\nThe laboratory investigations may reveal leukocytosis with elevated E.S.R. and C.R.P [3]. Serum levels of Lactate Dehydrogenase (S. LDH) are usually elevated and serve as a marker of disease activity and response to treatment [6].
\nThese clinico-radiological and laboratory parameters are akin to osteomyelitis and it requires a trained eye with high index of suspicion to pick the neoplastic nature early in order to avoid mistreating these patients. MRI scan (Fig 2 ) has emerged as one of the most important radiological investigation amongst the others, in the work-up of primary bone sarcomas. It helps immensely in delineating the marrow involvement, revealing skip lesions if any, understanding the extent of soft tissue component and its relationship with the neuro vascular bundle, joint involvement and to decide the ideal site for biopsy. M.R.I. can also be used to assess response to neo-adjuvant chemotherapy [3,5].<\/p>\n
\nStaging in a case of ES is of paramount importance because of its bearing on the overall prognosis and treatment decisions [1,3]. The conventional staging investigations included a C.T. scan of the chest, a three phase technetium mendronate bone scan and a bone marrow aspiration biopsy [3,10]. However, with the advent of P.E.T. C.T., the bone marrow aspiration biopsy is being found unnecessary [8,9].<\/p>\n
\nThe clinico-radiological suspicion of Ewing sarcoma has to be corroborated by a biopsy and pathological examination before further treatment is commenced. The biopsy of such a lesion is to be done preferably by the orthopaedic oncologist who will be treating the case, at a multi disciplinary cancer centre [3, 11, 13, 14, 15, 16, 17]. Most of the lesions are accurately diagnosed by a needle biopsy. Under the microscope, the tumor is arranged in sheets, nests or clusters of small round blue cells invading the native bone [1]. (Fig 3 a,b). The cells show dense blue chromatin with scanty cytoplasm and the contained glycogen is evident by the P.A.S. (periodic acid-Schiff) stain positivity. Immunohistochemical markers as CD 99 (a mic-2 gene product) and Fli-1 are diagnostic of Ewing sarcoma and are used as confirmatory tools [1,3].<\/p>\n