A Rare Case of Osteosarcoma and Rhabdomyosarcoma at the Same Site 7 Years Apart

Abstract not available. Introduction provided instead.

Three decades ago, most patients with bone sarcomas underwent amputation for survival. Since then, advances in diagnostic techniques and imaging modalities, neoadjuvant chemotherapy, and radiation therapy have facilitated limb-salvaging procedures, which are being performed routinely. Survival has also improved, with 5- and 10-year disease-free rates of 60% and higher.^1-3 With improved survival, treatment-related late complications are more likely to occur.⁴ One of the most significant complications in long-term survivors is development of a second malignant neoplasm (SMN).⁴ It is estimated that approximately 3% of survivors will develop a second malignant tumor within 20 years.^1,4 It is hypothesized that this predisposition to additional malignancies may be related to type of treatment used for the first cancer or to the patient’s genetic predisposition to malignancy.^1,4,5 Anthracyclines (eg, doxorubicin) have been associated with increased risk for developing a secondary soft-tissue sarcoma.⁴ Radiation therapy is also known to contribute to malignant transformation, though the relationship between relative risk and radiation dose has not been established.^1,6,7 Genetic disorders, such as Li-Fraumeni syndrome, neurofibromatosis, and retinoblastoma,
are well known to be associated with multiple neoplasms in different locations.⁸

Rhabdomyosarcoma is the most common soft-tissue sarcoma arising in children and adolescents.² Over the past 3 decades, multidisciplinary approaches to treating this cancer have raised the 5-year survival rate to more than 70%.^8,9 Several cases of a patient developing both rhabdomyosarcoma and osteosarcoma have been reported,^1,6,10 but each case involved radiation therapy in primary rhabdomyosarcoma subsequently leading to osteosarcoma in the radiation
zone. Recently, Dagdemir and colleagues¹¹ reported the case of primary pleomorphic rhabdomyosarcoma developing 5 years after limb-sparing surgery and neoadjuvant chemotherapy for osteosarcoma. However, the osteosarcoma
involved the femur, but the rhabdomyosarcoma occurred in the head of the humerus—that is, 2 separate and distinct anatomical locations.¹¹

In this article, we report the case of a patient who underwent limb-sparing surgery and chemotherapy for primary osteosarcoma of the distal femur and presented 7 years later with primary alveolar rhabdomyosarcoma in the same anatomical location.