Soft tissue tumors originating within the endobronchial tree are extremely rare and most of them correspond to lipomas or leiomyomas. We here report a rare clinical presentation of leiomyosarcoma mimicking glomus tumor at initial biopsy arising from the left main bronchial trunk leading to left lower lobe atelectasis. Primary leiomyosarcoma of the lung is an unusual malignancy. Among this entity, the endobronchial form is very rare and the preoperative diagnosis is extremely difficult. We documented two different presentations and outcomes of primary endobronchial leiomyosarcoma of the lung. In this clinical presentation, histological study and immunohistochemical stain of the surgical resection provided the final diagnosis. Through the following we present the diagnostic and therapeutic difficulties encountered with endobronchial leiomyosarcoma.