Sclerosing hemangioma (SH) of the lung is an uncommon tumor with a predilection for middle-aged women. This special phenomenon prompted us to examine SH for the expression of ERalpha (human estrogen receptor) and ERbeta (a second isoform of estrogen receptor). To investigate the staining pattern of these tumors, we also stained lung tissues from patients with non-small cell lung carcinomas and nonneoplastic type II pneumocytes for comparison. Thirty-seven pulmonary SHs and 301 non-small cell lung cancers specimens were explored. Expression of ERalpha and ERbeta was immunohistochemically measured. The overall frequency of overexpression for ERbeta was 91.9%. It was detected in both female (in 91.4% of 35 cases) and male (in 100.0% of 2 tumors from men) patients. There was ERbeta overexpression in all 9 tumors of solid pattern, 6 of 7 tumors of papillary pattern, all 4 tumors of sclerotic pattern, 12 of 13 tumors of hemorrhagic pattern, and 3 of 4 tumors of mixed pattern. The staining pattern of the neoplastic cells of the SH was similar to that of type II pneumocytes adjacent to the tumor rather than that of non-small cell lung cancers, in which the frequency of ERbeta overexpression was 45.8%. However, there was no ERalpha detectable in these neoplasms. Estrogen receptor beta overexpression is very frequent in pulmonary SHs, which is similar to that of alveolar cells but quite different from non-small cell carcinoma.