Servicio de Cirugía Ortopédica y Traumatología, Hospital Universitario Miguel Servet, Avda. de Isabel la Católica 1-3, 50009 Zaragoza, Spain.
J Pediatr Surg. 2011 Jul;46(7):E5-8. doi: 10.1016/j.jpedsurg.2011.03.075.
Myositis ossificans circumscripta (MOC), with nonneoplastic heterotopic bone formation in soft tissue and skeletal muscle, is rare in children. Extraskeletal osteosarcoma is a very rare malignant mesenchymal neoplasm of soft tissues in children. At onset, it may be difficult to distinguish MOC from a musculoskeletal infection or neoplasm, particularly in the absence of trauma, and a biopsy is frequently required. However, differentiating MOC from malignant neoplasm is imperative. We describe the case of a 22-month-old girl who presented with a benign fibrous-myofibroblastic tumor mimicking MOC. However, extraskeletal osteosarcoma was also considered in the differential diagnosis due to the absence of attachment of the lesion to the skeleton. Pathologic findings after a previous needle biopsy and posterior marginal resection exclude both differential diagnoses. Close follow-up during 3 years postoperatively showed no signs of recurrence.
局限性骨化性肌炎（MOC），是一种罕见的发生于软组织和骨骼肌的非肿瘤性异位骨形成。儿童的骨外骨肉瘤是一种非常罕见的软组织恶性间叶性肿瘤。在发病初期，MOC 可能难以与肌肉骨骼感染或肿瘤区分，特别是在没有外伤的情况下，通常需要进行活检。然而，区分 MOC 与恶性肿瘤是至关重要的。我们描述了一例 22 个月大的女孩，她表现为良性纤维-肌纤维母细胞瘤，类似于 MOC。然而，由于病变与骨骼无附着，也需要考虑骨外骨肉瘤的鉴别诊断。之前的针吸活检和后缘切除术的病理结果排除了这两种鉴别诊断。术后 3 年的密切随访未显示复发迹象。
