Pneumonectomy for Osteosarcoma Metastases: Two Compelling Cases With Unique Radiology

Abstract

Osteosarcoma, the most common primary bone tumor in young individuals, frequently metastasizes hematogenously to the lungs, necessitating pulmonary metastasectomy as a common surgical procedure. While sublobar and lobar resections are accepted approaches, pneumonectomy is considered a major intervention. In this report, we present 2 intriguing cases of patients who underwent pneumonectomy for pulmonary osteosarcoma metastases, emphasizing the challenges of careful patient selection and surgical planning.

Osteosarcoma, a primary bone tumor commonly diagnosed in the first 2 decades of life, often exhibits hematogenous dissemination to the lungs, leading to the frequent requirement of pulmonary metastasectomy.^1,2 While segmental resections are widely accepted surgical approaches for treating pulmonary metastases, pneumonectomy is considered a more extensive intervention. In this paper, we present 2 cases of patients who underwent pneumonectomies for pulmonary metastases, highlighting the difficulty in selecting patients for this procedure. The local behavior of osteosarcoma pulmonary metastases is emphasized.

Case Reports

Patient 1

A 29-year-old male patient presented with recurrent osteosarcoma 11 years after left-hand amputation for low-grade periosteal sarcoma. As high-grade histopathologic features were absent, systemic treatment was not administered. A thoracic computed tomography (CT) completed 8 years after definitive control of the primary osteosarcoma shows a calcified mass predominantly affecting the posterior segment of the right upper lobe (RUL) (Figure 1). The mass was encompassing the right interlobar bronchus and superior segmental bronchus, resulting in marked narrowing of the right lower lobe bronchus. Furthermore, there was an abnormal linear calcification process extending into the RUL, encasing its bronchovascular structures and veins. No aerated bronchi were observed in the posterior segment of the RUL. Calcified lymph nodes were present in the right hilar region but no other abnormal lymph nodes were detected.

Figure 1.

Coronal computed tomography reformat demonstrating an ossified mass at the right hilum narrowing the right upper lobe bronchus. Note the fingerlike ossified projections extending along the bronchovascular structures into the right upper lobe.

A positron emission tomography scan demonstrated abnormal metabolic activity solely in the right hilar mass. Based on full preoperative assessments and review at a multidisciplinary tumor board, the patient was deemed suitable for a right pneumonectomy. Bronchoscopy performed intraoperatively confirmed extrinsic compression of the RUL bronchus, while the right mainstem bronchus (RMB) appeared normal. After a right thoracotomy to assess the right hilum, a right pneumonectomy was deemed necessary. The right mainstem bronchus was divided near its bifurcation to minimize the length of the residual stump. Local-regional lymph nodes were harvested. The patient had an uneventful recovery and was discharged on postoperative day 4.

Pathologic examination confirmed metastatic high-grade osteosarcoma in the RUL, involving the RMB. The tumor showed areas of firmness with sharp fingerlike bony projections and malignant spindle cell proliferation, along with osteoid formation and abnormal woven-type bone. All harvested lymph nodes were negative. Surprisingly, the tumor extended to the RMB margin. The patient received adjuvant cisplatin and doxorubicin; however, treatment was discontinued after 2 cycles due to severe neurologic and ototoxicity, and reactivation of herpes zoster-varicella. At 13-month follow-up there was concern for relapse at the bronchial stump.

Patient 2

A 45-year-old male individual who had undergone surgical treatment for left leg osteosarcoma at the age of 16 years was found to have a fungating lung mass on CT 29 years later (Figure 2). CT demonstrated complete obstruction of the left upper lobe bronchus with abnormal ossified soft tissue extending along the bronchovascular structures at the hilum and narrowing the left pulmonary artery and the left lower lobe bronchus. This was confirmed bronchoscopically. Biopsy results indicated atypical spindle cell proliferation consistent with metastatic osteosarcoma. A positron emission tomography scan demonstrated intense uptake in the left upper lobe (LUL) tumor with no evidence of disseminated disease. After review at a multidisciplinary tumor board, the patient was found to be a good candidate for left pneumonectomy.

Figure 2.

Axial computed tomography demonstrating complete obstruction of the left upper lobe bronchus with abnormal ossified soft tissue extending along the bronchovascular structures at the hilum and narrowing the left pulmonary artery and the left lower lobe bronchus.

Intraoperatively, it was evident that the tumor extended into the left atrium and therefore an intrapericardial left pneumonectomy with partial atrial resection was performed to achieve a negative margin. The procedure and postoperative course were uncomplicated. The patient was discharged home on postoperative day 7.

Surgical pathology revealed a 9.5-cm high-grade metastatic osteosarcoma, predominantly located in the LUL, with bone formation extending across the fissure and into the hilum. Notably, the lateral aspect of the mass contained a bony protruding area. All margins and nodes were negative.

The patient completed 6 cycles of adjuvant cisplatin and doxorubicin with minimal side effects. Clinically and radiographically, the patient remains disease-free at 46 months.

Comment

Osteosarcoma is the most prevalent primary bone tumor during the first 2 decades of life.^1,2 More than 80% of recurrences present with pulmonary metastases.^2,3 CT chest plays a crucial role in confirming the diagnosis and characterizing suspected lung metastases, typically presenting as multiple well-defined nodular deposits in the lung parenchyma, with or without ossification. However, atypical radiologic thoracic features, such as large, ossified lung masses, cavitation, hemorrhagic metastases, and tumor thrombi, have also been documented.³ Awareness of these atypical findings is vital to facilitate timely diagnosis and accurate surgical planning. Resection of pulmonary metastases and multi-agent chemotherapy have demonstrated improved outcomes for osteosarcomas.^2,4

We present 2 intriguing cases of patients with unique radiographic presentations of pulmonary metastases occurring 11 and 29 years after the primary lesion was resected. Osteosarcoma metastases presenting as large, ossified lung lesions have been previously reported^5,6; the cases presented here involve central lesions with extension along luminal structures. In Case 1, the tumor was observed to extend along the bronchial tree, while in Case 2, an ossified spur extended into the left atrium, and more extension along the bronchus was noted than expected. Both patients received adjuvant cytotoxic chemotherapy.

Pneumonectomy should be carefully considered in patients with metastatic osteosarcoma involving the lung hilum. Preoperative imaging needs to be meticulously studied. Although not used in either case presented here, 3-dimensional reconstruction of preoperative imaging should be considered. The decision to perform pneumonectomy should be based on a thorough evaluation of the patient's overall health, extent of disease, the disease-free interval from treatment of the primary tumor to occurrence of the pulmonary metastasis, and the feasibility of achieving complete resection. It is noteworthy that pneumonectomy is generally considered a major surgical intervention with potential risks and complications. Therefore, patient selection is crucial to ensure that the benefits outweigh the risks.

In Case 1, the patient presented with osteosarcoma metastases in the RUL with extension along the bronchial tree. The decision for a right pneumonectomy was made after confirming extrinsic compression of the RUL bronchus during intraoperative bronchoscopy. After 13 months there is disease recurrence at the RMB. It is notable that the primary lesion was low-grade osteosarcoma while the pneumonectomy specimen contained high-grade osteosarcoma.

Similarly, Case 2 presented a unique challenge with a large LUL mass extending into the left hilum involving the left atrium. Intraoperative assessment revealed the possibility of obtaining a negative margin with a left intrapericardial pneumonectomy and partial resection of the left atrium. This intricate procedure was successfully performed, and the patient completed adjuvant chemotherapy.

In selected patients amenable to complete resection, pneumonectomy appears to play a crucial role in achieving disease control. Both cases support this, despite the complexities involved in performing pneumonectomy for osteosarcoma metastases. The proximal bronchial margin was closer than anticipated in both cases, and therefore the use of intraoperative frozen section should be liberally utilized. Moreover, the role of adjuvant chemotherapy in treating osteosarcoma pulmonary metastases should be considered. While chemotherapy has shown to be beneficial in some cases,^2,4 it can also be associated with adverse effects, as seen in Case 1 where treatment had to be discontinued.

In conclusion, the presented cases highlight the significant challenges of pneumonectomy in patients with osteosarcoma pulmonary metastases. However, the decision for pneumonectomy should be made cautiously, with consideration of potential benefits and risks associated with the procedure. Advances in preoperative imaging and surgical techniques have improved patient outcomes. Further research and long-term follow-up of such cases will provide valuable insights into optimizing the management of pulmonary metastases in osteosarcoma patients.