Ewing's sarcoma of the pelvis: an unusual, but not to be missed, cause of an irritable hip

Abstract

A 15-year-old girl presented with a 2-month history of non-specific right hip pain associated with pain in the back, right flank and foot. Her symptoms deteriorated, interfering with weight-bearing. Following admission, she was found to be febrile with a flexion deformity of her right-hip, and tenderness over the iliac crest and posterior pelvis. A markedly elevated C reactive protein and erythrocyte sedimentation rate, with an ultrasound-proven scan effusion within the right hip were all suggestive of septic arthritis. However, full blood count demonstrated a significant anaemia, which together with the tenderness around the pelvis was not in keeping with this diagnosis. Surgical washout was therefore delayed to obtain a MRI scan of the pelvis. The scan revealed a 5×5×3 cm necrotic soft tissue mass within the gluteal muscles, arising from the right ilium, which biopsy confirmed to be a Ewing's sarcoma.

Sarcoma de Ewing pélvico: o grande imitador

“…Fever, weight loss, anemia and increased inflammatory markers are uncommon unspecific manifestations. 1 7 8 Radiographs feature lytic destruction and subperiosteal bone formation similar to “onion skinning.” 1 4 5 8 These features are most easily detected in long bones in comparison with the pelvis. The value of radiographs in the pelvis is compromised by the anatomy of the iliac bone and of overlying structures.…”

“… 1 5 Early magnetic resonance imaging (MRI) for soft tissue characterization and, to a lesser extent, identification of a “sharp transition zone”, is useful. 3 7 These nonspecific clinical and imagiological findings may be present in conditions such as metastatic carcinoma, malignant lymphoma, osteomyelitis, 4 fibrous dysplasia 5 or eosinophilic granuloma (EG), 9 making its early diagnosis challenging. 1 2 3 4 5 6 7 8 9 The definitive diagnosis is made by open biopsy and histological examination combined with immunochemistry and cytogenetics.…”

“… 3 7 These nonspecific clinical and imagiological findings may be present in conditions such as metastatic carcinoma, malignant lymphoma, osteomyelitis, 4 fibrous dysplasia 5 or eosinophilic granuloma (EG), 9 making its early diagnosis challenging. 1 2 3 4 5 6 7 8 9 The definitive diagnosis is made by open biopsy and histological examination combined with immunochemistry and cytogenetics. 1 4 The lack or insufficiency of histologic specimens by percutaneous biopsy may lead to its misdiagnosis.…”

“…Febre, perda de peso, anemia e aumento de marcadores inflamatórios são manifestações inespecíficas incomuns. 1 7 8 Radiografias apresentam destruição lítica e formação óssea subperiosteal semelhante a "esfolar cebola". 1 4 5 8 Essas características são mais facilmente detectadas em ossos longos em comparação com a pelve.…”

“… 1 5 A ressonância magnética (RM) precoce para caracterização de tecidos moles e, em menor grau, a identificação de uma "zona de transição acentuada", é útil. 3 7 Esses achados clínicos e imaginológicos não específicos podem estar presentes em condições como carcinoma metastático, linfoma maligno, osteomielite, 4 displasia fibrosa 5 ou granuloma eosinofílico (EG, na sigla em inglês), 9 tornando seu diagnóstico precoce desafiador. 1 2 3 4 5 6 7 8 9 O diagnóstico definitivo é feito por biópsia aberta e exame histológico combinado com imunoquímica e citogenética.…”