Osteosarcoma of the metatarsal bone

A case of osteosarcoma arising from a metatarsal bone is reported, focusing on the radiological findings and differential diagnosis. Received: 16 November 1998 Revision requested: 17 December 1998 Revision received: 11 January 1999 Accepted: 14 January 1999     

Clear cell chondrosarcoma mimicking chondroblastoma in a skeletally immature patient

We report the case of a clear cell chondrosarcoma (CCCS) occurring in the femoral head of a 14-year-old skeletally immature boy. Radiographic examination revealed a well-defined, osteolytic lesion in the epiphysis of the femoral head. Given the patient's age and the radiographic appearance of the lesion, chondroblastoma was high on the differential diagnosis. A frozen section was performed at the time of open biopsy was felt to be consistent with either chondroblastoma or CCCS. CCCS in a skeletally immature patient was felt to be unlikely, so curettage and bone grafting was performed. Final pathology review, however, confirmed the diagnosis of CCCS. The patient was taken back to surgery 4 weeks later for a wide resection and hemiarthroplasty.     

Intracortical osteoblastic osteosarcoma with oncogenic rickets

Intracortical osteosarcoma is the rarest variant of osteosarcoma, occurring within, and usually confined to, the cortical bone. Oncogenic osteomalacia, or rickets, is an unusual clinicopathologic entity in which vitamin D-resistant osteomalacia, or rickets, occurs in association with some tumors of soft tissue or bone. We present a case of oncogenic rickets associated with intracortical osteosarcoma of the tibia in a 9-year-old boy, whose roentgenographic abnormalities of rickets disappeared and pertinent laboratory data except for serum alkaline phosphatase became normal after surgical resection of the tumor. Histologically, the tumor was an osteosarcoma with a prominent osteoblastic pattern. An unusual microscopic feature was the presence of matrix mineralization showing rounded calcified structures (calcified spherules). Benign osteoblastic tumors, such as osteoid osteoma and osteoblastoma, must be considered in the differential diagnosis because of the relatively low cellular atypia and mitotic activity of this tumor. The infiltrating pattern with destruction or engulfment of normal bone is a major clue to the correct diagnosis of intracortical osteosarcoma. The co-existing radiographic changes of rickets were due to the intracortical osteosarcoma.     

Primary osteosarcoma of a metatarsal bone

Although osteosarcoma is the most common primary bone malignancy of childhood and adolescence that is not related to marrow cells, involvement of the short tubular bones is uncommon. In contrast to more conventional sites, where the tumor is usually high grade and found in adolescents, osteosarcoma of the small bones is more likely to be low grade, and is often seen in older individuals. We present a case of low-grade primary osteosarcoma of a metatarsal bone in a 25-year-old woman. Received: 22 December 1998 Revision requested: 3 February 1999 Revision received: 24 April 2000 Accepted: 26 April 2000     

Clear-cell chondrosarcoma with elevated alkaline phosphatase,mistaken for osteosarcoma on biopsy

 This paper report a case of a pelvic clear-cell chondrosarcoma that was initially diagnosed as clear-cell osteosarcoma after needle biopsy. Preoperatively, laboratory studies revealed an elevated alkaline phosphatase and needle biopsy showed clear cells producing osteoid. Internal hemipelvectomy was performed and final pathology was most consistent with clear-cell chondrosarcoma, despite a negative S-100 immunohistochemical stain. Distinguishing between these two entities is clinically important because treatment differs. In this case, the patient did not receive pre- or postoperative chemotherapy and is disease free more than 2 years later.     

Multifocal osteosarcoma as second tumor after childhood retinoblastoma

We present a case of multifocal osteosarcoma (MFOS) arising 11.5 years after successful treatment of bilateral retinoblastoma. The clinical, imaging and pathological findings at onset, after therapy, and during follow-up are described. Fluorescent in situ hybridization did not reveal a deletion of the RB-1 retinoblastoma gene, although the presence of an inactivating mutation invisible to this method cannot be ruled out. The MFOS may have been a second multifocal tumor associated with the original retinoblastoma or a post-irradiation sarcoma with extensive metastases. Received: 20 November 1998 Revision requested: 5 January 1999 Revision received: 8 March 1999 Accepted: 19 March 1999     

Osteosarcoma in a patient with McCune-Albright syndrome and Mazabraud’s syndrome

Sarcomas infrequently develop in osseous sites of fibrous dysplasia. We report a patient with Mazabraud’s syndrome (polyostotic fibrous dysplasia and soft tissue myxomas) complicated by the development of osteogenic sarcoma in a bone affected by fibrous dysplasia. This is the third case of osteosarcoma within the small population of reported patients with Mazabraud’s syndrome. There may be an increased incidence of malignant transformation in these individuals’ dysplastic bones above that associated with patients suffering from fibrous dysplasia alone. Received: 31 December 1998 Revision requested: 31 January 1999 Revision received: 13 May 1999 Accepted: 14 May 1999     

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     

Recurrent, multiple, calcified soft tissue metastases from osteogenic sarcoma without pulmonary involvement

Osteosarcoma (osteogenic sarcoma) metastasizes primarily to the lung. With the introduction of neoadjuvant chemotherapy as part of the treatment, the overall and disease-free survival rates have dramatically improved. In this case report, a young man with multiple soft tissue and bone metastases, including a rare large bone-forming retroperitoneal metastasis, is described. Despite the extensive extrapulmonary metastases, the patient did not develop pulmonary metastases in the 4 years following initial presentation of the primary tumour. Received: 16 December 1998 Revision requested: 14 January 1999 Revision received: 30 July 1999 Accepted: 1 August 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     

Metastatic bone tumor mimicking spontaneous osteonecrosis of the medial condyle of the femur: misleading appearance on MR imaging

We report a case of a metastatic bone tumor that mimicked spontaneous osteonecrosis of the medial condyle of the femur on magnetic resonance imaging. Received: 5 October 1999 Revision requested: 11 November 1999 Revision received: 10 January 2000 Accepted: 17 January 2000     

Deep soft tissue leiomyoma of the thigh

A case of ossified leiomyoma of the deep soft tissues of the left thigh is presented. The radiographic appearance suggested a low-grade chondrosarcoma. MRI of the lesion showed signal characteristics similar to muscle on both T1- and T2-weighted spin echo sequences with linear areas of high signal intensity on T1-weighted images consistent with medullary fat in metaplastic bone. Histopathological examination of the resected specimen revealed a benign ossified soft tissue leiomyoma. Received: 23 December 1998 Revision requested: 31 January 1999 Revision received: 11 March 1999 Accepted: 16 March 1999     

Osteogenic sarcoma with skeletal muscle metastases

Two cases of osteogenic sarcoma with skeletal muscle metastases are described. A 40-year-old woman presented with progressive swelling of both calves and a soft tissue back lump. She had been diagnosed with mandibular chondroblastic osteogenic sarcoma 6 years earlier. Radiographs showed calcified masses. MRI scans and bone scintigraphy revealed multiple soft tissue masses in both calves. Bone scintigraphy also showed uptake in the back lump, right thigh and left lung base. Biopsy confirmed metastatic chondroblastic osteogenic sarcoma, which initially responded well to chemotherapy. However, the metastatic disease subsequently progressed rapidly and she died 21 months after presentation. The second case concerns a 20-year-old man who presented with a pathologic fracture of the humerus, which was found to be due to osteoblastic osteogenic sarcoma. He developed cerebral metastases 17 months later, followed by metastases at other sites. Calcified masses were subsequently seen on radiographs of the abdomen and chest. CT scans confirmed the presence of densely calcified muscle metastases in the abdominal wall, erector spinae and gluteal muscles. The patient’s disease progressed rapidly and he died 30 months after presentation. Received: 16 November 1998 Revision requested: 28 December 1998 Revision received: 18 January 1999 Accepted: 18 January 1999     

Peritumoral edema in osteoid osteoma on magnetic resonance imaging

Objective.To determine whether there is a relationship between the peritumoral edema caused by osteoid osteoma seen on magnetic resonance (MR) imaging and the patient’s age, duration of symptoms, or location of the lesion. Design and patients. All histologically proven osteoid osteomas seen in our institutions during a 5-year period in patients with known age, gender, duration of symptoms, and available radiological and MR imaging examinations were included in this study. The extent of the edema in the bone marrow and extraosseous soft tissue around the nidus of osteoid osteoma on T2-weighted MR imaging were graded from 1 (nonexistent) to 4 (extensive) by two masked observers. The relationships between the patient’s age, duration of symptoms, and location of lesions were evaluated by Pearson’s correlation coefficient and analysis of variance. Results.Twenty-seven cases met the inclusion criteria. The observer agreement on grading was good. Patients of 15 years of age or younger had significantly higher grades than patients older than 15 years. There was a moderate negative linear correlation between the patient’s age and peritumoral edema. No significant relationship was identified between edema and the duration of symptoms or the location of lesions. Conclusion. Osteoid osteomas in younger patients tend to be associated with more extensive peritumoral edema. Received: 13 March 1998 Revision requested: 3 August 1998 Revision received: 12 January 1999 Accepted: 2 March 1999     

Chondromyxoid fibroma of two thoracic vertebrae

We report on a case of chondromyxoid fibroma involving two adjacent thoracic vertebrae with features of aggressive behaviour on radiographs, CT and MRI. Histology revealed typical chondromyxoid fibroma with unusually coarse calcifications. Chondromyxoid fibroma of the spine is rare, and only 30 of these tumours have been reported so far. Involvement of two contiguous vertebral bodies by chondromyxoid fibroma, as reported here, appears exceptional. Received: 10 August 1998 Revision requested: 14 September 1998, 29 December 1998 Revision received: 22 December 1998, 19 January 1999 Accepted: 21 January 1999     

Fracture of the lateral process of the talus: appearance at MR imaging and clinical significance

The case of a 59-year-old man with chronic lateral ankle pain following an inversion injury is presented. MR imaging performed to evaluate for soft tissue injury revealed an unsuspected fracture of the lateral process of the talus. The patient underwent surgical exploration of the fracture with debridement of adjacent loose bodies and is currently undergoing aggressive physical rehabilitation. Received: 23 November 1998 Revision requested: 18 December 1998 Revision received: 4 January 1999 Accepted: 4 January 1999     

Primary clear cell sarcoma of bone: a unique site of origin

Clear cell sarcoma is a rare soft tissue neoplasm, accounting for less than 1% of soft tissue sarcomas. We are presenting a case of a clear cell sarcoma of bone which, to our knowledge, is the only report of a primary clear cell sarcoma of bone. Received: 23 June 1998 Revision requested: 29 July 1998 Revision received: 11 December 1998 Accepted: 17 December 1998     

Oncogenic osteomalacia

The clinical, imaging, metabolic, histologic and biochemical aspects of oncogenic osteomalacia are reviewed. The bone and soft tissue tumor and tumor-like lesions associated with this paraneoplastic syndrome are discussed. The radiologist’s role in the diagnosis and evaluation of this entity is presented. Received: 11 November 1999 Revision requested: 30 December 1999 Revision received: 7 January 2000 Accepted: 10 January 2000     

Solitary infantile myofibromatosis involving the clavicle

A rare case of solitary infantile myofibromatosis of bone is reported in the right clavicle of a 15-year-old boy. A radiograph demonstrated an osteolytic lesion with a sharp margin and a sclerotic rim. CT revealed a circumscribed lesion with slight expansion of the cortex. On MRI the lesion appeared isointense to muscle on T1-weighted images, bright on T2-weighted images, and showed marked gadolinium enhancement. The patient was well, without evidence of recurrence or metastasis, 4 years and 5 months following resection. Received: 11 August 1998 Revision requested: 5 October 1998, 18 March 1999 Revision received: 15 March 1999, 23 April 1999 Accepted: 28 April 1999     

Parosteal lipoma with hyperostosis

A case of parosteal lipoma of the femur combined with hyperostosis is presented. The parosteal lipoma is a rare benign tumor containing adipose tissue and is intimately related to the periosteum. We report the MRI features and correlative pathologic findings of a parosteal lipoma. The MRI technique is useful for evaluating the relationship between the periosteum and the lipoma. Received: 5 November 1998; Revision received: 11 January 1999; Accepted: 10 February 1999