Benign lung tumors: Introduction

B lung tumors are uncommon neoplasms comprising less than 1% of all resected lung tumors. Other nonbronchogenic, primary pulmonary malignancies account for 3% to 5% of lung tumors and, with the exception of carcinoid and hamartomas, most of these unusual neoplasms have fewer than 100 cases reported in the literature. Although numerous classification schemes for these rare tumors have been devised, none has become widely accepted. Consideration of these tumors is important because they surface in the differential diagnosis of patients with solitary or multiple pulmonary nodules, requiring differentiation from common bronchogenic carcinoma or patients with suspected pulmonary metastasis. The term “benign” is often misinterpreted, with a variety of low-grade malignancies casually referred to as “benign” by patients and their physicians. Prime examples of the debatable use of the benign designation are pulmonary carcinoid tumor, and stage I thymoma. Although these neoplasms have a low metastatic potential, they still should be considered low-grade malignancies to prevent the false sense of security implied by the benign designation. In fact, one of the interesting and paradoxic tumors discussed in this issue is the benign metastasizing leiomyoma (ie, evidence of confusion and contradiction of terminology and natural history). However, for purposes of completeness, we have included typical carcinoid tumors within this issue because of their low malignant grade and common interpretation as “benign” tumors. The 5 papers in this section are each from experienced and eminent clinicians and investigators in general thoracic surgery. The article by Drs. McMullan and Wood covers the most common, low-grade pulmonary neoplasm (ie, the typical, pulmonary carcinoid tumor). This article provides a current overview of the spectrum of neuroendocrine tumors of the lung, ranging from typical carcinoid to small cell carcinoma, and the evolution of a variety of pathologic classification schemes. It goes on to emphasize the key components of diagnosis, work-up, and treatment of carcinoid tumors. One of the highlights is the useful role of endobronchial therapeutics for relieving airway obstruction caused by carcinoid tumors to prepare patients better for subsequent surgery. The other key feature emphasized is the importance of bronchoplastic procedures for achieving complete resection with pulmonary preservation, given the common endobronchial and central location of these tumors. The second article on hamartomas by Drs. Whyte and Donington reviews the most common benign tumor of the lung if pulmonary carcinoid tumors are excluded. These tumors account for approximately 75% of all benign lung tumors and 4% of all solitary pulmonary nodules. The authors review the radiologic hallmarks of these neoplasms, along with their natural history and treatment. This article emphasizes the controversy regarding indications for surgery and the unique technical aspects of excision via enucleation. The article by Dr. Mitchell reviews the subject of solitary fibrous tumors of the pleura. Although this is truly a pleural-based neoplasm, it often presents as pulmonary nodules, with similar work-up and treatment and, therefore, should be included in any consideration of benign lung neoplasms. The interesting characteristic of these lesions is that they often present as very large endothoracic masses, sometimes combined with the systemic findings of hypertrophic pulmonary osteoarthropathy and/or hypoglycemia. Dr. Mitchell emphasizes that despite their large size, these tumors are nearly always benign and resectable with a limited pulmonary resection. As such, treatment of these benign endothoracic neoplasms is often the most gratifying to patient and surgeon alike. From the Division of Cardiothoracic Surgery, University of Washington, Health Sciences, Seattle, WA. Address reprint requests to Doulgas E. Wood, Division of Cardiothoracic Surgery, University of Washington, Health Sciences, 1959 NE Pacific, Room AA-115, Box 356310, Seattle, WA 98195-6310. © 2003 Elsevier Inc. All rights reserved. 1043-0679/03/1503-$30.00/0 doi:10.1016/S1043-0679(03)00077-7