Strikingly, TTF-1 is positive in 83% of cases. Irving and Young [13] described a series of 32 cases of lung carcinoma metastatic to the ovary, 14 of which were metastasis of SCLC and, interestingly, case number 8 had a concomitant Sertoli-Leydig tumor, which explains the atypical clinical presentation. This evidence concerns the gene TTF1 and small cell lung carcinoma.