A clinicopathologic analysis of 88 lung resections of suspected metastatic carcinomas with proven primaries

The lung is the most common site for metastatic carcinomas. Very few studies have comprehensively analyzed all pulmonary resections for metastatic carcinomas.

To analyze all lung resections for suspected metastatic carcinomas accrued over 10 years to evaluate: (i). The most frequent primary site,(ii). The interval between primary tumor diagnosis and lung metastases, and (iii). The proportion of inadvertently resected benign lesions, clinicoradiologically mistaken for metastatic deposits.

Between 2002 and 2011, 88 pulmonary metastasectomies were done for suspected metastatic carcinomas, which form the basis of this study.

In 81 of 88 cases (92%) the diagnosis of metastatic carcinoma was histologically confirmed, whereas 7 cases (8%) were non-neoplastic. The mean interval between primary tumor and metastases was 2.5 years. The primary sites were colorectum (30; 37%), kidney and breast (14; 17.3% each), cervix (9; 10%), salivary gland carcinoma (3), thyroid carcinoma (2), squamous carcinoma (2, one each of mandible and larynx), papillary urothelial carcinoma (2), hepatocellular carcinoma (1), endometrioid adenocarcinoma (1), carcinosarcoma of endometrium (1), adrenocortical carcinoma (1), and neuroendocrine carcinoma (1). The 7 non-neoplastic lesions (8%) histologically revealed tuberculosis (4), bronchopneumonia (2), and aspergillosis (1).

Almost three fourths (71.6%) of the metastatic pulmonary resections comprised primaries from colorectum, breast and kidney. The interval between primary tumor and metastases ranged from zero months to 10 years (mean 2.5 years). Tuberculosis was the most common histologic diagnosis among the 8% of the non-neoplastic lesions, which were mistaken for metastatic carcinoma on clinical evaluation.