Endobronchial Primary Pulmonary Leiomyoma Causing Recurrent Pneumonia

Abstract Introduction: Pulmonary leiomyoma is a benign smooth muscle neoplasm first described in the early 1900's. Leiomyomas account for approximately 2% of all lung tumors. Here we describe a case of endobronchial leiomyoma presented as recurrent pneumonia. Case Presentation: A 35-year-old female presented with a right lower lobe endobronchial lesion. She suffered from pneumonia twice in one calendar year which prompted a tomographic scan of her chest. An endobronchial lesion was found partially occluding the basilar segment of the right lower lobe with associated post-obstructive pneumonia. She underwent bronchoscopy which revealed an endobronchial tumor occluding the basilar segments with patency of the superior segment and right middle lobe bronchus. The tumor was ablated with argon plasma coagulation and subsequently extracted in bulk using the cryoprobe. The lesion was composed of intersecting fascicles of monomorphic spindle cells strongly highlighted by actin and desmin while lacking pancytokeratin or β-catenin. The lesion lacked high-grade cytologic atypia consistent with pulmonary leiomyoma. Follow up imaging revealed patent distal right lower lobe airways with no evidence of recurrence. Discussion: Pulmonary leiomyomas are amongst the rarest of benign pulmonary tumors. While leiomyomas account for approximately 2% of all lung tumors, primary endobronchial leiomyoma account for 0.66%. The diagnosis favors females to males with a ratio of 2:1 with mean age of diagnosis in the third or fourth decade of life. Pulmonary leiomyoma is a tumor of the smooth muscles of the bronchi and bronchioles having been identified throughout the respiratory tree from the trachea to the segmental airways, but rarely have been identified as solitary nodules, pleural lesions, or involve the pulmonary artery or vein. There are currently no guidelines on the management of the disease with both bronchoscopic as well as surgical resections having been described. Various endobronchial ablative techniques have been reported such as radiofrequency ablation, cryoablation, Nd-YAG laser, or mechanical debridement. Primary leiomyoma should be differentiated from the more common benign metastatic leiomyoma arising from a primary in the uterus often presenting as multiple lung nodules. Conclusion: Pulmonary leiomyomas are a very rare benign tumor of the lower respiratory tract. The initial presentation of symptoms may be highly variant from symptoms of airways disease such as wheezing, cough, or infection to a solitary pulmonary nodule. Treatment is surgical with varying approaches based on anatomic location and co-morbidities. This case supports an emerging case series of lung-sparing bronchoscopic interventional techniques to address this rare tumor.