Metastasis to the Lung From Carcinomas of Nonpulmonary Sites After Prolonged Disease-free Intervals.

Background: Most carcinomas of nonpulmonary sites that metastasize to the lung do so within 5 years of diagnosis. Although examples of late metastasis to the lung after prolonged disease-free intervals (>5 y) have been reported sporadically, this phenomenon has not been systematically analyzed. The aim of this study was to describe the clinical and pathologic features of metastases to the lung from carcinomas of nonpulmonary origin after prolonged disease-free intervals.

Methods: We searched our pathology archives to identify lung biopsies/resections containing metastases from carcinomas of nonpulmonary origin. Medical records were reviewed to determine the interval between resection of the nonpulmonary primary and subsequent detection of lung metastasis. Cases were included if the disease-free interval between initial diagnosis and lung metastasis exceeded 5 years and the site of origin could be verified by pathologic examination.

Results: Of 195 consecutive lung metastases from carcinomas of nonpulmonary sites, the recurrence-free interval before lung metastasis was >5 years in 20 (10.3%). Primary sites (number of cases, recurrence-free interval) included kidney (5, 6 to 33 y), endometrium (5, 8 to 10 y), colon (3, 6 to 13 y), breast (2, 8 y, 12 y), esophagus (1, 8 y), thyroid (1, 10 y), epiglottis (1, 12 y), prostate (1, 12 y), and ovary (1, 15 y). At diagnosis of lung metastasis, lung nodules/masses were multiple in 12 and solitary in 8.

Conclusions: Carcinomas of nonpulmonary sites can metastasize to the lung after prolonged disease-free intervals and present as a solitary lung mass. The most common culprits are carcinomas of the kidney and endometrium.