Extraskeletal osteosarcoma of the jaw

Extraskeletal osteosarcoma is a rare malignancy, which accounts for 1–2% of all soft tissue sarcomas; occurrence of these tumors in the head and neck is extremely rare. We present a case of extraskeletal osteosarcoma arising in the subcutaneous tissue of the jaw angle, the central portion of which displayed calcification. Imaging findings were interesting in terms of a high grade malignancy in that the tumor was small and well circumscribed; its appearance mimicked a calcified lymph node. The differential diagnosis of this lesion as well as the imaging and pathological features of extraskeletal osteosarcoma are discussed.     

The stone man: myositis (fibrodysplasia) ossificans progressiva

Myositis ossificans progressiva (MOP) is a rare hereditary connective tissue disorder characterized by progressive ossification of striated muscle and connective tissue associated with pain and disability. It is presumably transmitted as an autosomal dominant defect. Congenital anomalies of the hands and feet are early signs of this disease. Involvement of the spine, hips and extremities lead to the development of the “stone man” with only less than 600 cases reported in the literature. We present a case of MOP with typical muscle ossifications and skeletal malformations. Received: 25 November 1996; Revision received 31 January 1997; Accepted 13 February 1997     

骨化性肌炎的X线、CT及MRI表现

列示病变呈高等低混杂信号,边界不清.晚期T1WI和T2WI均呈低信号,周边无水肿.MRI增强各期病变及其周围软组织无明显强化.结论 骨化性肌炎影像表现具有一定特征,根据病程分析可更全面地显示其特点.     

骨化性肌炎的临床和MRI表现分析

目的:分析骨化性肌炎的临床和MRI表现特点,以提高其诊断和鉴别诊断的能力。方法:对16例经手术或穿刺病理证实为骨化性肌炎患者的临床和MR检查图像进行回顾性分析。结果:外伤后四肢痛性软组织肿块是其主要临床表现,T2WI上见有团块和分叶状不均匀信号、边缘有低信号带形成的软组织肿块,周围有显著的水肿带是其特征性的MRI表现。结论:骨化性肌炎临床上多有外伤史,MRI表现具有一定的特征性,提高对其MR表现的认识有助于诊断和鉴别诊断,避免不必要的手术。     

Telangiectatic dedifferentiation of a parosteal osteosarcoma

A unique case of parosteal osteosarcoma (POS) of the proximal femur, with areas of telangiectatic dedifferentiation, in a 28-year-old woman is reported. The patient had a 7-week history of pain and swelling in her right thigh. A biopsy diagnosis of POS was established. The patient was treated with two cycles of intra-arterial chemotherapy, followed by limb salvage surgery. Histological examination of the resected specimen showed POS with areas of dedifferentiation composed of high-grade telangiectatic osteosarcoma with associated secondary aneurysmal bone cyst change. Received: 17 April 1998 Revision requested: 11 May 1998 Revision received: 9 May 2000 Accepted: 11 May 2000     

Extraskeletal osteochondroma of the foot

A case of pathologically proven extraskeletal osteochondroma is presented with magnetic resonance imaging (MRI), computed tomography (CT), bone scan and radiographic findings. The diagnosis of extraskeletal osteochondroma should be considered when a discrete, ossified mass is localized in the soft tissues of the distal extremities. Nomenclature surrounding this entity is controversial and is discussed. Received: 22 March 1999 Revision requested: 26 April 1999 Revision received: 22 May 1999 Accepted: 24 May 1999     

Osteoblastoma-like osteosarcoma

We report an osteoblastoma-like osteosarcoma in the right proximal fibula in a 22-year-old woman. Radiographs showed an irregular osteolytic lesion from the metaphysis to the epiphysis in the proximal fibula with partial destruction of cortical bone. Tissue from a biopsy indicated a typical osteoblastoma. Curettage and bone graft was performed. One year after the surgery, local recurrence occurred, and a wide excision was performed. Histological examination of the en-bloc surgical specimen revealed the tumor had permeated through the host bony trabeculae, although the nuclear atypia was not marked. Immunohistochemical expression of MIB-1 was detected in 9.0% of cells. Received: 22 May 2000 Revision requested: 23 June 2000 Revision received: 10 July 2000 Accepted: 13 July 2000     

Ossifying fibromyxoid tumor resembling parosteal osteosarcoma

Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue neoplasm which varies in the amount of bone tissue laid down. We report on a case of OFMT in a 59-year-old male which mimicked a large parosteal osteosarcoma on radiography, MRI, and CT. T1-weighted MR images showed high-intensity areas which reflected fatty marrow. The metaplastic bone was connected to the cortex of the femur, but the tumor did not involve the medullary cavity. The tumor was irradiated and the patient was administered chemotherapy. Wide excision of the tumor and hip rotation plasty was performed. The patient has been disease free for 18 months.     

The imaging features of post-traumatic myositis ossificans,with emphasis on MRI

Post-traumatic myositis ossificans is a benign condition of heterotopic bone formation, which can mimic soft-tissue and bone malignancies. This pictorial review describes the specific imaging features of myositis ossificans using different imaging techniques, but with emphasis on MRI.     

Dedifferentiated parosteal osteosarcoma with rhabdomyosarcomatous differentiation

Dedifferentiated parosteal osteosarcomas are characterized histologically by the combination of low-grade fibroblastic osteosarcoma admixed with a high-grade component that typically has the appearance of malignant fibrous histiocytoma or osteosarcoma. Herein we report a case of dedifferentiated parosteal osteosarcoma of the distal femur, in which the high-grade component consisted of rhabdomyosarcoma. To our knowledge, a rhabdomyosarcomatous component has not been described previously in a dedifferentiated parosteal osteosarcoma. The clinical, radiologic, and pathologic features of this rare type of surface osteosarcoma are described. Received: 1 March 1999 Revision requested: 6 April 1999 Revision received: 27 Apri1 1999 Accepted: 29 April 1999     

Low-grade parosteal osteosaracoma of the ulna with dedifferentiation into high-grade osteosarcoma

 This report describes a low-grade parosteal osteosarcoma of the ulna with dedifferentiation into high-grade osteosarcoma. The clinical, pathological, and imaging findings are described and discussed.     

Iliopsoas myositis mimicking appendicitis: MRI diagnosis

 Myositis of the truncal muscles can closely mimic acute appendicitis. Myositis is the early stage of muscular infection. It is characterized by diffuse muscular pain and swelling without a distinct mass. Early diagnosis of myositis improves the outcome and surgical debridement is usually avoided. Pyomyositis, the advanced stage of the disease, can be diagnosed by MRI examination. We present a case of early bacterial myositis that was diagnosed by MRI.     

99mTc-methylene diphosphonate and 67Ga-uptake in myositis ossificans

A histologically proven case of myositis ossificans is presented. Both ^99mTc-MDP and ⁶⁷Ga imaging demonstrated extensive uptake of radiotracers in the lesion.     

Multicentric malignant transformation of multiple exostoses

We treated a patient with large multiple chondrosarcomas derived from multiple cartilaginous exostoses. One sarcoma originated in the left pubic bone and the other sarcoma in the posterior aspect of the greater trochanter of the left femur. Thirty months after hindquarter amputation, the patient is alive without relapse. This is the first report of a patient with synchronous multiple malignant transformation of multiple cartilaginous exostoses.     

Extraskeletal myxoid chondrosarcoma of the knee

Extraskeletal myxoid chondrosarcoma is an uncommon neoplasm, accounting for less than 2% of all soft tissue sarcomas. It affects adult males with a median age in the fifth decade at the time of diagnosis. The tumor usually arises in the deep soft tissues, especially in the lower extremities. Patients present with a gradually enlarging mass that may or may not be associated with pain. This report describes a 25-year-old man who initially presented with a 4- to 5-year history of right knee pain and an enlarging mass in the right knee. Evaluation revealed a cartilaginous neoplasm with no evidence of metastatic disease. The tumor was widely excised and an allograft reconstruction was performed. The patient was closely followed with an eventual above the knee amputation for recurrent myxoid chondrosarcoma. At 34 months, retroperitoneal metastases were noted on abdominal CT. The patient underwent a left radical nephrectomy, renal vein thrombectomy and enucleation of the mass in the right kidney, distal pancreatectomy, and splenectomy. The patient received postoperative chemotherapy. Forty-eight months after initial diagnosis, the patient was found to have recurrent abdominal and retroperitoneal lesions. At 64 months, the patient died from complications of extraskeletal myxoid chondrosarcoma. Received: 6 July 1998 Revision requested: 7 August 1998 Revision received: 29 January 1999 Accepted: 3 February 1999     

Post-Paget telangiectatic osteosarcoma of the skull

Sarcomatous transformation is the most dreaded complication of Paget’s disease. We report on a case of post-Paget telangiectatic osteosarcoma of the skull, a variant of osteogenic osteosarcoma, in a 79-year-old woman. We discuss the radiological pattern in relationship to the differential diagnosis. Received: 27 July 1998 Revision requested: 24 August 1998, 23 December 1998 Revision received: 25 November 1998, 12 April 1999 Accepted: 13 April 1999     

Soft tissue osteosarcoma with telangiectatic features: MR imaging findings in two cases

Extraskeletal osteosarcomas are rare tumors, and the telangiectatic variety is the least common histological variety in this group. This report describes the clinical and MR imaging findings in two cases arising in the pretibial soft tissues. Both tumors demonstrated marked inhomogeneity with T2-weighted spin echo and STIR sequences. One of the tumors revealed numerous fluid levels within the lesion. A review of the MRI features of these tumors is provided. Osteosarcoma with telangiectatic features should be considered in the differential diagnosis of a soft tissue mass with fluid-fluid levels in patients 40 years of age or older.     

Parosteal osteosarcoma of a metatarsal with intramedullary invasion

A 70-year-old man presented with increasing swelling of 2 years’ duration, on the dorsal aspect of the forefoot. Imaging studies revealed a heavily calcified surface lesion of bone with early invasion of the underlying second metatarsal. Both imaging findings and the subsequent resection histology were consistent with a parosteal osteosarcoma, which is particularly rare at this site and at this age. The differential diagnosis of a mineralizing surface lesion of bone arising in the foot is discussed. Received: 2 June 1998 Revision requested: 8 August 1998 Revision received: 16 November 1998 Accepted: 17 November 1998     

Intracortical osteosarcoma

Intracortical osteosarcomas originate in the bone cortex and represent the rarest type of osteosarcoma. We describe the clinical, radiological and histological features of an intracortical osteosarcoma occurring in the femur of a young man and discuss the pertinent features of this tumour compared to those previously reported.