Precordial chest pain lasting for 2 weeks. Physical examination revealed increased temperature (38.5°C), a palpable supraclavicular lymph node and tenderness over the knee (the patient recalled recent injury).
The patient presented to ER complaining of precordial chest pain lasting for 2 weeks. Physical examination revealed increased temperature (38.5°C), a palpable supraclavicular lymph node and tenderness over the knee (the patient recalled recent injury). Blood test revealed anemia, mild leukocytosis and increased ALP, LDH and VES.
Radiographs of the right knee demonstrated extensive metaphyseal, diaphyseal and epiphyseal lesions in the right femur, predominantly osteosclerotic, with aggressive periosteal reaction (Codman triangle) and soft-tissue swelling. Plain film of the right femur showed intramedullary poorly defined sclerotic lesions throughout the diaphysis(Fig.1). The findings were suspicious for malignant bone tumor and he was referred for CT study.
CT scan of the femur-knee joint confirmed the findings of the radiographs, demonstrated extensive soft-tissue mass and showed the involvement of the tibia (Fig. 2). Chest CT scan revealed multiple calcified intraparenchymal and pleural nodules and small pleural effusion (Fig. 3). In addition, on abdominal CT scan multiple calcified nodules were shown in the subcutaneous tissue and retroperitoneum bilaterally (Fig. 4). Biopsy of a neck lymph node revealed typical histological features of osteosarcoma. Considering the imaging findings the diagnosis of a synchronous multicentric osteosarcoma was made.
Osteosarcoma is the commonest primary neoplasm of the bones in children and adolescents and the second most common primary malignant bone tumor, after multiple myeloma in adults. The most common form is the high grade intramedullary variant also called conventional osteosarcoma.
Histologically, it is classified as a malignant mesenchymal neoplasm containing tumor cells producing osteoid or immature bone.
Long bones are typically affected. The most frequent sites are distal femur, proximal tibia (knee bones) and proximal humerus. Metaphysis is involved in the majority of cases and extension into the epiphysis occurs mainly in cases with open physis. Primary involvement of the diaphysis or epiphysis is very rare.
Clinical presentation includes pain, swelling, and enlargement of the extremity. Pathologic fracture may be seen at presentation or during therapy. Trauma can bring the lesion to clinical attention.
X-rays typically demonstrate a mixed sclerotic and lytic lesion arising in the metaphyseal region of the affected bone (fluffy, cloudlike opacities within the lesion). This pattern is accompanied by aggressive periosteal reaction (codman triangle, sunburst, hair-on-end) and by soft tissue swelling.
CT is often helpful when the disease involves anatomically complex areas such as the pelvis. CT, MRI and bone scintigraphy are used for preoperative assessment and staging. Intraosseous extent is present in the same bone or across an adjacent joint("skip" metastases). Metastases of osteosarcoma have been reported to occur in the lungs, lymph nodes, liver, spleen, kidneys, pancreas, pleura, small-bowel, muscles, heart, skin, brain.
In several cases, there is more than one lesion at the time of presentation. Multiple foci arise most frequently in several tubular bones, symmetrical or not. This entity is called multicentric osteosarcoma (multifocal osteosarcoma or osteosarcomatosis). Although older studies consider osteosarcomatosis as a primary disease, recently, there is great evidence that the condition represents an unusual form of metastatic osteosarcoma. Based on histology, age of the patient and the time of presentation of lesions, multiple classifications have been referred.
From the review of the literature only 262 cases have been reported. The common features were identified:
a) multiple radiodense lesions that present simultaneously or within 5 months of the initial presentation, with or without pulmonary metastases;
b) a single “dominant” lesion with multiple, symmetric or not, smaller lesions;
c) a uniformily, rapid, fatal prognosis.
The dominant lesion has similar features to conventional or primary solitary osteosarcoma. The secondary foci are usually better defined, more sclerotic and smaller, without periosteal or cortical reaction.
In conclusion, we present a patient with synchronous multicentric osteosarcoma. This case illustrates a pattern of a dominant lesion (right distal femur) and multiple skeletal and extraskeletal foci at the time of presentation.
Synchronous multicentric osteosarcoma
Based on the provided X-ray and CT images, the following features can be observed:
1. A mixed-density lesion in the distal right femur (near the knee joint), characterized by both osteolytic destruction and sclerosis. Locally, there appears to be “cloud-like” or “ground-glass” dense areas, suggesting new tumoral bone formation. Significant soft tissue swelling can also be seen. An aggressive periosteal reaction is suspected, including a “Codman’s triangle” and a sunburst-like radiating pattern.
2. Multiple small nodules in the lungs on CT, with shape and density suggestive of metastatic nodules. Some lesions are adjacent to the hilum or pleura, indicating possible pulmonary or pleural metastases.
3. Abdominal CT indicates abnormal high-density lesions or masses in the liver, spleen, and other organs, suspected to be metastases. Some bowel segments appear thickened, raising the possibility of tumor invasion or peritoneal metastasis.
4. Other skeletal sites (such as the contralateral femur or other long bones) may show varying degrees of sclerosis or osteolytic lesions, suggesting multiple skeletal lesions.
Overall, the lesion in the distal right femur appears extensive and aggressive, combined with multiple pulmonary metastases and metastases in other bones or organs, fitting the imaging characteristics of a primary malignancy with multiple metastases or multicentric disease.
Considering the patient’s age, knee pain with local swelling, the prominent tumorous changes on imaging in the distal right femur, and the presence of multiple lesions in the lungs, abdomen, and other bones, the most consistent diagnosis is
“Multicentric (Synchronous) Osteosarcoma.”
It is recommended to perform a biopsy (especially of the distal right femur lesion) for pathological confirmation, along with laboratory tests (such as serum alkaline phosphatase), to finalize the diagnosis.
1. Treatment Plan:
(1) Neoadjuvant Chemotherapy: A multi-drug chemotherapy regimen is commonly used in osteosarcoma to control tumor growth and reduce micrometastases.
(2) Surgical Treatment: If the pathology confirms osteosarcoma, a decision should be made—based on the clinical situation—between limb-salvage surgery or amputation to remove or eradicate the tumor, while also addressing metastatic lesions.
(3) Postoperative Adjuvant Chemotherapy or Radiotherapy: To further eliminate potential residual microscopic disease.
(4) Comprehensive Systemic Therapy: Given the presence of multiple metastatic lesions, close monitoring of lung and abdominal metastases is necessary. Symptomatic treatment and consideration of other local or systemic reinforcement therapies may be required.
2. Rehabilitation and Exercise Prescription:
(1) Early Postoperative Rehabilitation: For limb-salvage procedures, under the guidance of professional rehabilitation therapists, begin with passive range-of-motion exercises and joint mobilization of the affected limb, then gradually introduce light weight-bearing. For amputation cases, focus on stump care, limb strengthening, and gradual prosthesis fitting.
(2) Muscle Strength and Cardiopulmonary Training in the Recovery Period: Engage in moderate activities such as swimming and aerobic training (e.g., seated or recumbent cycling). Maintain basal metabolic level and cardiopulmonary function. Gradually increase training duration to 20–30 minutes per session, 3–5 times a week, depending on tolerance.
(3) Advanced Exercise Phase for Mid- to Late Rehabilitation: If the surgical and chemotherapy outcomes are stable, gradually include resistance training such as elastic band exercises, light weight-bearing exercises, and balance coordination practice, as recommended by physicians or therapists. Each session’s intensity should aim for “mild fatigue but still manageable,” and be adjusted individually.
(4) FITT-VP Principle: Throughout rehabilitation, adjust Frequency, Intensity, Time, Type, Volume, and Progression based on the patient’s physical capacity, areas of disease, and response to treatment. Ensure safety while steadily enhancing functional capacity, and avoid excessive fatigue or injury.
(5) Special Considerations: Given multiple osteolytic lesions and surgical incisions, it is crucial to avoid excessive loading and strenuous movements. Chemotherapy may also affect cardiopulmonary function, making close monitoring of heart rate, blood pressure, and respiration essential.
This report is based solely on the current radiological and clinical information available and does not substitute for in-person medical consultation or the opinion of a professional physician. The actual diagnosis and treatment plan should be determined through a multidisciplinary team evaluation, involving orthopedic oncology, radiology, pathology, and other relevant specialties, according to the patient’s specific clinical situation.
Synchronous multicentric osteosarcoma
