Clinical outcome of parosteal osteosarcoma.

BACKGROUND: Parosteal osteosarcoma is a rare type of osteosarcoma with distinct characteristics. Clinical outcome of 21 patients was analyzed to assess the predictive relevance of surgical margin, intramedullary tumor extension and histologic grade. METHODS: There were 5 mens and 16 womens with an average age of 26 years. Average follow-up was 9.1 years (range 2.5-22.1). Most common sites were distal femur (15) and proximal humerus (2). No patient presented with metastasis. Surgical margin was wide in 13 and marginal in 8. Intramedullary extension was seen in 10 patients (48%). Focal high-grade 2 and 3 tumors were seen in 11 (52%) and 3 (14%) patients respectively. RESULTS: Twenty patients (95%) were alive without disease. Two (10%) had relapse, one with local recurrence and another with local recurrence and lung metastasis. Of eight marginal procedures performed, 2 turned out to have histologically tumor-positive margins, both of whom later developed relapses. All patients with histologically negative margins remained disease-free. Presence of intramedullary extension and focal high-grade tumor was not significantly associated with relapse. CONCLUSIONS: A marginal but histologically negative margin of excision appears adequate for parosteal osteosarcoma. However, long-term follow-up is warranted for monitoring of rare incidences of local recurrences or distant metastases.

Parosteal osteosarcoma with myocardial metastasis 13 years after follow-up.

PURPOSE: To report the case of a woman with a diagnosis of grade II (low grade) parosteal osteosarcoma with the occurrence of myocardial metastasis 13 years after resection, and to present a review of the existing literature on the subject. METHODS: Description of the case and review of the literature. CONCLUSION: The review leads to the conclusion that the occurrence of metastasis from parosteal osteosarcoma can occur in up to 38% of the cases, in spite of its relatively low aggressiveness. However, myocardial metastasis of a parosteal osteosarcoma is an event that was not found in the literature.

Parosteal osteosarcoma with myocardial metastasis 13 years after follow-up

PURPOSE: To report the case of a woman with a diagnosis of grade II (low grade) parosteal osteosarcoma with the occurrence of myocardial metastasis 13 years after resection, and to present a review of the existing literature on the subject. METHODS: Description of the case and review of the literature. CONCLUSION: The review leads to the conclusion that the occurrence of metastasis from parosteal osteosarcoma can occur in up to 38 percent of the cases, in spite of its relatively low aggressiveness. However, myocardial metastasis of a parosteal osteosarcoma is an event that was not found in the literature

The role of imaging modalities in the diagnosis of primary dedifferentiated parosteal osteosarcoma.

Dedifferentiated parosteal osteosarcoma (dd-POS) is defined as high-grade sarcomatous components coexisting with low-grade POS components. With regard to the histological diagnosis of dd-POS, the sampling of a small area of dedifferentiation through the densely mineralized POS can be a problem. In this situation, imaging is important to identify the area with the highest possibility of dedifferentiation. We report a patient in whom dedifferentiation was shown by computed tomography (CT) and magnetic resonance imaging (MRI). CT revealed a radiolucency in a highly mineralized area. T2-Weighted MRI showed a relatively high signal intensity, corresponding to the radiolucency, surrounded by a very low signal intensity area. Furthermore, gadolinium-enhanced T1-weighted MRI showed marked enhancement. Based on these imaging techniques, the condition was diagnosed as most likely to be a dd-POS, although a representative sample was not accessible by incisional biopsy. Neoadjuvant chemotherapy was administered, followed by wide resection and adjuvant chemotherapy. Four years after the surgery, partial lobulectomy was required because of a pulmonary metastasis. Three years after the second surgery, the patient remained well without evidence of metastases. Based on the initial diagnosis and, consequently, the optimal treatment of combined chemotherapy and wide resection, our patient showed a good clinical outcome.

Parosteal osteosarcoma of the tarsus.

Parosteal osteosarcoma is a very rare bone tumor with a predilection for the posterior aspect of the distal femoral metaphysis. A case of parosteal osteosarcoma of the tarsus of a 23-year-old woman is reported. This is the second case of parosteal osteosarcoma of the tarsus reported in the English literature.