Journal of Pediatric Surgery (2011) 46, 574–576
www.elsevier.com/locate/jpedsurg
Metastatic osteosarcoma presenting as a single pulmonary microembolus Mark Shapiro a,⁎, Birte Wistinghausen b , Peter Midulla c , Cynthia Chin d a
Department of Surgery, The Mount Sinai Medical Center, Box 1259 New York, NY 10029, USA Division of Pediatric Hematology/Oncology, The Mount Sinai Medical Center, Box 1259 New York, NY 10029, USA c Division of Pediatric Surgery, The Mount Sinai Medical Center, Box 1259 New York, NY 10029, USA d Division of Thoracic Surgery, The Mount Sinai Medical Center, Box 1259 New York, NY 10029, USA b
Received 13 November 2010; revised 2 January 2011; accepted 2 January 2011
Key words: Osteosarcoma; Pulmonary embolism; Tumor embolus; Pneumonectomy
Abstract There are only a few published reports of tumor emboli from osteosarcoma. We are reporting a 17-year-old adolescent boy with a history of localized osteosarcoma who developed a symptomatic pulmonary artery tumor embolus. He was initially diagnosed with a pulmonary thromboembolism. This is the first reported case of a single tumor embolus developing after surgical resection of a tumor with 100% necrosis after chemotherapy and no evidence of metastatic disease at the time of surgery. Pulmonary tumor embolism should be considered in the differential diagnosis in patients with cancer who present with dyspnea. The differentiation of tumor embolus from other causes of dyspnea is important for treatment plan. © 2011 Elsevier Inc. All rights reserved.
It is well documented that patients with malignancies can develop pulmonary metastasis. However, pulmonary tumor embolism is not often described in the literature. This is a case of a 17-year-old adolescent boy with a history of osteosarcoma who developed a symptomatic pulmonary artery tumor embolus. There are only a few published reports of tumor emboli from osteosarcoma, and this is the first reported case of a single tumor embolus developing after surgical resection of a tumor with 100% necrosis after chemotherapy and no evidence of metastatic disease at the time of surgery. ⁎ Corresponding author. Tel.: +1 212 241 5871; fax: +1 212 410 0111. E-mail addresses:
[email protected] (M. Shapiro),
[email protected] (B. Wistinghausen),
[email protected] (P. Midulla),
[email protected] (C. Chin). 0022-3468/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2011.01.001
1. Case report The patient is a 17-year-old adolescent boy with a localized osteosarcoma of the left femur who was treated with chemotherapy followed by limb preservation surgery. At presentation, the patient had a computed tomography (CT) of the chest and a positron emission tomography (PET) done, which were negative for metastasis or skip lesions. The pathology of the resected tumor mass showed 100% tumor necrosis with clear margins. He presented 1 month later with fevers and acute onset of right-sided chest pain. A CT scan with contrast showed a small filling defect in the superior segmental branch of the right pulmonary artery and an adjacent area of consolidation (Fig. 1). The CT also showed 7.3 × 3.4 cm area of consolidation with an adjacent 2.3 × 1.6 cm cavitary lesion within the right lower lobe. This was consistent with pulmonary embolus (PE) and
Metastatic osteosarcoma as a pulmonary microembolus
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Fig. 1 Computed tomographic scan showing pulmonary artery filling defect at initial presentation. Fig. 3 Computed tomographic scan showing a mass adjacent to a pulmonary artery at the time of hemoptysis.
possibly a superimposed infection. As part of the work up for PE, the patient had lower extremity and abdominal ultrasound and cardiac echocardiogram done, which were negative for thrombus. Treatment with low–molecular weight heparin was initiated, and antibiotic coverage was given for a pulmonary infectious process. During the following year, the patient was admitted twice with complaints of chest pain, once when he was off anticoagulation and the second time while on low–molecular weight heparin. During the second admission, his CT angiogram showed persistent filling defect (Fig. 2), and his lovenox was continued. The patient had an episode of hemoptysis 3 months later. A repeat CT angiogram showed the previous pulmonary artery filling defect with an adjacent 3 × 4 cm lobular mass (Fig. 3). On the PET scan, this area had a standardized uptake value (SUV) of 9.5. The probability of metastatic osteosarcoma was discussed with his family, and the patient was taken to the operating room for resection. Owing to the central location of the tumor and its adherence to the main pulmonary artery, a pneumonectomy was performed to obtain adequate margins. The patient had an uneventful
Fig. 2 Computed tomographic scan showing persistent filling defect 6 months after initial presentation.
recovery and was discharged home on postoperative day 6. The pathology specimen showed a 4.3-cm mestastatic osteosarcoma mass in the pulmonary artery with direct invasion into the adjacent parenchyma. The margins were negative for tumor. Postoperatively, the patient received high-dose ifosfamide and etoposide chemotherapy, which he tolerated without complications. Twenty-nine months after surgery, the patient had no evidence of disease.
2. Discussion Since the first report of pulmonary tumor embolus in 1897 by Schmidt [1], tumor embolus of this nature have been found at autopsy in 2.4% to 26% of patients with solid organ tumors [2]. It can be difficult to distinguish pulmonary tumor embolism from other pulmonary disease commonly seen in a patient with malignancy and immunosuppression. It is well documented that cancer and postsurgical patients have a higher risk for venous thrombosis. Clinical symptoms of a thrombotic pulmonary embolism vs a tumor embolism are indistinguishable. Our case highlights the difficulty and importance of making the correct diagnosis. This patient had a 100% tumor necrosis at the time of first surgery without any signs of metastasis, making the diagnosis of tumor embolism even more unlikely. Most reports of tumor emboli are in patients with epithelial-derived tumors. Only a few cases of pulmonary tumor embolism from sarcoma have been reported and, unlike our patient, these patients had extensive emboli involving multiple segments of pulmonary arteries [3-7]. It has been published that tumor emboli on ventilationperfusion scans are characteristically seen as numerous perfusion defects with a symmetrical and peripheral distribution [8]. We would not have seen this in our patient who had a solitary, central metastasis.
576 Furthermore, a report published by Paz-Priel et al [9] reviewed the records of 122 children and adolescents with sarcoma and found 16% rate of thromboembolic events without mentioning of any events of tumor embolism. These results suggest that, in children with sarcoma, clinically evident thromboembolic events are much more common than a tumor embolism. The fact that, in our patient, ultrasound of the lower extremities was negative for deep venous thrombosis (DVT) could have raised suspicion of etiology for PE being other than thrombus. However, studies have shown that, in the presence of a confirmed PE, ultrasound is negative for DVT in 20% to 50% of patients [10]. One of the largest studies analyzing the rate of the resolution of an acute pulmonary embolism using CT imaging showed that only 48% of patients had complete resolution of PE after mean follow-up of 10.5 months [11]. Thus, continued presence of a filling defect in the pulmonary artery in our patient should not have necessarily increased our suspicion of tumor PE. However, a higher index of suspicion for a tumor embolus at the second admission might have lead to a diagnosis of tumor embolus, and therefore, treatment could have been initiated before the rapid growth seen on CT scan 3 months later. In summary, this case report shows that pulmonary tumor embolism should be considered in the differential diagnosis of a patient with cancer who presents with dyspnea and CT findings consistent with pulmonary embolism. Even having only a single filling defect does not exclude the possibility of a tumor embolism. If there is high index of suspicion for tumor embolus, undergoing a PET scan may help in the diagnosis of tumor metastasis. Differentiating tumor embolism from thrombotic embolism is important because
M. Shapiro et al. of the vastly different therapy that would be initiated. In this case, an earlier diagnosis may have allowed a smaller lung resection.
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