Primary Osteosarcoma of the Rib Identified on Bone Scintigraphy

A case report of rib osteosarcoma and literature review

About half of osteosarcomas occur near the knee joint, but other sites such as the humerus, upper femur, fibula, spine, and ilium can also occur. However, rib osteosarcoma is rarely reported. Here, we report the case of a 17-year-old female who was found to have a left dorsal mass on physical examination. Computed tomography (CT) revealed bone destruction in the seventh rib, leading to surgery for mass excision. Pathological results suggested chondroblastic osteosarcoma. After surgery, the patient was treated with chemotherapy and is doing well.

Solitary Thumb Acrometastasis Identified on Bone Scintigraphy

A 45-year-old man with a history of adenocarcinoma in the right lung 3 years ago underwent a Tc-MDP bone scan to evaluate possible osseous metastasis. The images demonstrated intense activity in the region of left thumb, while the tracer uptakes in other bones were not typical of metastases. A CT of the hand showed diffuse sclerotic changes with destructed trabecular structure in the proximal phalanx of the left thumb. The left thumb was subsequently resected, and the pathological examination of the resected left first metacarpal bone confirmed the diagnosis of metastasis of lung adenocarcinoma.

The Management Challenges in an Unusual Case of Primary Osteosarcoma of the Rib in an Adult Patient

Primary osteosarcomas are derived from primitive bone-forming mesenchymal stem cells and most often originate in the metaphysis of the long bones of children and adolescents, but it occurs very rare in adults. Approximately 10% of osteosarcomas are located in the flat bones, pelvis being the main site. Involvement of flat bones like rib may be seen as a metastatic process or secondary to chemotherapy, but a primary osteosarcoma rib is extremely rare. Osteosarcoma originating from such rare sites poses numerous diagnostic and therapeutic challenges, and we report one such case in a 24-year-old male patient. Our case highlights the fact that osteosarcoma of the rib, although rare, should be considered in the differential diagnosis of primary malignant neoplasms of the rib even in the adult population. Further, early prompt diagnosis and aggressive multimodality management are cornerstones of management and will help improve the survival outcomes.