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Uncommon Pulmonary Metastases and Metastasectomy: A Review

Abstract

Rani Kanthan, Senger JL and Kanthan SC

Background: The development of pulmonary metastases is a critical step in oncology management as it is a major determinant of survival for patients with cancer. Primaries that commonly metastasize to the lung arise from breast, head/neck, and the gastrointestinal tract. The aim of this study was to review the pathobiogenesis of pulmonary metastases and the evolution of curative pulmonary metastasectomy as reported in the literature in addition to analyzing in detail uncommon pulmonary metastatic lesions received over a period of 14 years.
 
Design: The indexed uncommon pulmonary metastases were reviewed and analyzed in detail. A 14-year (1996-2010) computer-based review using the Laboratory-Information-System was conducted in our laboratory. Results were categorized based on age, sex, and primary sites of origin with special emphasis to study unusual pulmonary metastases.
 
Results: 230 cases of pulmonary metastases were retrieved on review. 129 females (56%) and 101 males (44%) ranging in age from 19 months to 91 years (median 65 years) were identified with their primary sites of origin being: breast (28.3%), gastrointestinal tract (27.8%), kidney (8.7%), and melanoma (7.0%). Three uncommon diagnoses were identified and studied in detail: 1) an index case of metastatic benign pleomorphic adenoma, case series of 2) endometrial stromal sarcoma and 3) osteosarcoma.
 
Conclusion: Due to the poor prognosis of metastatic lung cancer, early recognition with accurate diagnosis is an important step for optimal patient management. In this context, pathologic awareness of uncommon metastases remains a challenging task. Pulmonary metastasectomy is a curative option for an increasing number of patients due to recent advances in chemotherapy that achieve locoregional control of the primary tumours. With this increased number of pulmonary metastasectomy, recognition of not only ‘common’ pulmonary malignancies but also more rare entities becomes central to best practices in surgical pathology.