Metastatic Osteosarcoma

Abstract

A 25-year-old man presented with increasing shortness of breath and sputum production of 2 weeks' duration. He denied hemoptysis, chest pain, fever, or chills. Examination revealed absent breath sounds over the left hemithorax with stony dullness to percussion. His history was remarkable for osteosarcoma of the right femur 2 years before presentation with subsequent surgical resection and neoadjuvant therapy. A chest x-ray demonstrated total opacification of the left hemithorax. Bronchoscopy was performed demonstrating left main bronchial obstruction secondary to an exophytic, necrotic fungating tumor mass, which was extending proven to be metastatic osteosarcoma by biopsy (Fig. 1).FIGURE 1: Osteosarcoma arising from the left main bronchus and extending into the trachea.Pulmonary metastasis secondary to osteosarcoma is well described; however, luminal spread with endobronchial or endotracheal obstruction is rarely described. DISCUSSION The lungs remain the second most common organs affected by metastatic carcinoma, with 20% to 54% of all patients demonstrating pulmonary metastasis sometime during their disease. Highest propensity for pulmonary metastasis is seen with choriocarcinoma, osteosarcoma, testicular tumors, melanoma, Ewing sarcoma, and Kaposi sarcoma.1 This is the result of the fact that lungs act as the capillary drainage filter for most organs with nonpulmonary neoplasms metastasizing to the lungs through the lymphatic system and pulmonary carcinoma via the hematogenous route.1,2 Despite the frequent metastatic involvement of the lungs, the rate of endobronchial or endotracheal metastasis from nonpulmonary metastasis is variable, with reports ranging from 2% to 50% depending on whether invasion from parenchymal mass or lymph nodes are included.3-5 In Heitmiller et al's review of the Johns Hopkins experience with endobronchial metastasis, they noted that breast carcinoma accounted for 52.2%, renal cell carcinoma in 17.4%, colonic adenocarcinoma in 13%, and carcinoma of the bladder, thyroid, ovary, and nasopharynx in 4.3% each.6 Kiryu et al delineated developmental modes for such metastatic pulmonary involvement: type I with direct metastasis to the bronchus, type II with bronchial invasion by a parenchymal lesion, type III with bronchial invasion by mediastinal or hilar lymph node metastasis, and type IV with peripheral pulmonary lesions extending along the proximal bronchus. Differing developmental modes could have variable median survival times owing to differences in pathogenesis and clinical significance of each mode.3 Osteosarcoma is the most common skeletal malignancy of childhood with metastatic disease to the lungs found in the majority of patients succumbing to this tumor.7,8 Osteosarcoma could also arise in patients with Paget's disease, enchondromatosis, hereditary multiple exostoses, and fibrous dysplasia and most commonly affects the metaphysis of long tubular bones such as the distal femur and proximal tibia.9 On initial workup, approximately 10% to 20% of patients with osteosarcoma will have metastasis with greater than 70% of patients having the lung as the sole site of metastasis.7,10,11 With the introduction of chemotherapy beginning in the 1970s, the 5-year survival rate has improved to 32% to 40% and the incidence of pulmonary metastasis has fallen from 92% to 31%.8 Surgical wedge resection of lung metastasis is potentially curative in 25% to 40% for those patients in whom the primary lesion is under control and complete resection is possible.10,12-15 Significant prognostic factors include the number of nodules, disease-free interval, and resectability of nodules with the presence of 3 nodules or less to be the single most important prognostic factor. Also, if the disease-free interval, described as the time from the primary operation to the date of the first lung recurrence, was greater than 6 months, the median survival increased from 12 to 38 months.16 This patient presented had life-threatening obstruction of the tracheobronchial tree. Patients such as this with unresectable yet symptomatic obstruction for whom regional treatment could improve quality of life are candidates for therapeutic bronchoscopic procedures. Such procedures could include Nd-YAG laser, electrosurgery argon plasma coagulation, or cryotherapy with or without concurrent stent placement.17 The endotracheal extension of this patients mass was noted to have an overlying soft tissue consistency, which was ablated with a combination of Nd-YAG laser and argon plasma coagulation. Mechanical debulking of the calcified component of the tracheal extension was followed by subsequent placement of an expandable metallic stent (Ultraflex; Boston Scientific Co., Boston, MA).