Multidisciplinary approach to the accurate diagnosis of parosteal osteosarcoma.

The successful treatment of any disease depends on early and correct diagnosis. A failure to establish an accurate diagnosis can lead to ineffective, often expensive treatment and risky progression of the disease with all the negative consequences, including incurability and death. The parosteal osteosarcoma is an illustrative example of how determining the correct diagnosis can be a challenging task. Parosteal osteosarcoma is a rare malignant bone tumor, mainly affected metaphysis of long bones. It arises from cortical surface of bone and it is usually slowly growing, low-grade, and well-differentiated tumor with good prognosis. Unfortunately, parosteal osteosarcoma is often misdiagnosed as a benign osteochondroma or myositis ossificans what leads to ineffective treatment, disease progression and systemic spreading with later treatment complications. In this article, we discuss a case of 48-years-old male with prolonged diagnosis of parosteal osteosarcoma, initially misdiagnosed as myositis ossificans. The diagnosis was revised and corrected based on results obtained by various approaches, including radiography, ultrasound-guided biopsy, histology, conventional cytology, and molecular biology. On this example, we demonstrate the importance of interdisciplinary collaboration between experts from different areas of health care.