INTRODUCTION: Leiomyosarcomas are rare smooth muscle tumors commonly found in the female genital tract, gastrointestinal tract, and soft tissues. When found in the lung these neoplasms are typically metastatic lesions. However they may present as primary pulmonary neoplasms. As of 2001 fewer than 100 cases of primary pulmonary leiomyosarcoma had been reported. We report a case of primary pulmonary leiomyosarcoma with complete obstruction of the left main bronchus with exophytic growth creating a near total obstruction of the right mainstem bronchus and respiratory distress. Respiratory compromise was relieved through tumor resection using argon plasma coagulation.
CASE PRESENTATION: A 50-year-old African American woman presented with a one-month history of cough, productive of dark sputum, pleuritic chest pain, and dyspnea on exertion. The patient reported two uterine myomectomies performed four and eight years prior to presentation. Both samples were found to be benign uterine fibroids. The patient's past medical history was otherwise unremarkable. She denied tobacco use and second hand smoke exposure. Chest auscultation revealed pronounced wheezing in the left mid-lung. Blood chemistries and cell counts were within normal limits. Upon initial evaluation chest CT revealed two masses: a well-circumscribed, heterogeneous, 5.8 cm × 4.1 cm mass within the lingua of the lung abutting the left heart border and a 2.0 cm × 2.9 cm mass abutting the left mainstem bronchus. No mediastinal or axillary adenopathy was discovered on CT. Bronchoscopy revealed an obstructing lesion of the left upper lobe bronchus. Endobronchial biopsy, cytopathology, and immunohistochemical staining confirmed a diagnosis of high-grade leiomyosarcoma. Negative gynecologic and gastrointestinal evaluation confirmed the lung as the primary tumor. The tumor was debulked with rigid bronchoscopy, and medical therapy with Gleevac, and pallative radiation therapy were employed. Twenty-five months after initial presentation the patient presented to the emergency room with acute respiratory distress and stridor. Emergent bronchoscopy was preformed which identified progressive tumor invasion of the trachea which was producing a ball valve effect on the right mainstem bronchus resulting in near complete obstruction of the right mainstem bronchus during inspiration. Argon plasma coagulation was employed for resection of the right mainstem obstruction, reliving the patient's respiratory distress and stridor.
DISCUSSIONS: Pulmonary leiomyosarcomas predominate in men and typically occur in the sixth decade or later. These lesions originate from lung smooth muscle in four fashions: adjacent to or within a bronchus or pulmonary artery, as a sub-pleural nodule, or as intraparenchymal mass unrelated to bronchial or vascular structures.1,2 Presentations vary as signs and symptoms are based on tumor location. As with our patient, endobronchial leiomyosarcomas are typically symptomatic presenting with cough, expectoration, hemoptysis, or dyspnea. Where as tumors associated with the pulmonary artery typically present with chest pain, dyspnea, and/or intractable congestive heart failure. Pulmonary leiomyosarcoma classically present on chest radiograph as a homogeneous, lobulated mass, with a sharply defined margins.1 CT scan classically reveals multifocal lesions, endobronchial obstruction and the absence of hilar lymphadenopathy. Although primary pulmonary leiomyosacroma's are know for endobronchial obstruction, review of the literature returned no reported cases of bilateral mainstem obstruction secondary to exophytic endobronchial growth.
CONCLUSION: Primary pulmonary leiomyosarcoma is a rare tumor that has the potential to lead to respiratory compromise through advanced endobronchial invasion. In certain cases tumor extension may lead to bilateral mainstem bronchi obstruction requiring emergent bronchoscopic resection.
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