Abstract: Sclerosing hemangioma (SH), an unusual benign pulmonary neoplasm, was first described by Liebow and Hubbell1Liebow A.A. Hubbell D.S. Sclerosing hemangioma (histiocytoma) of the lung.Cancer. 1956; 9: 53-75Crossref PubMed Scopus (279) Google Scholar in 1956. It occurs predominantly in middle-aged women.2Devouassoux-Shisheboran M. Hayashi T. Linnoila R.I. Koss M.N. Travis W.D. A clinicopathologic study of 100 cases of pulmonary sclerosing hemangioma with immunohistochemical studies: TTF-1 is expressed in both round and surface cells, suggesting an origin from primitive respiratory epithelium.Am J Surg Pathol. 2000; 24: 906-916Crossref PubMed Scopus (264) Google Scholar Most patients have no symptoms, with the tumors being detected incidentally during routine chest radiographic examination. Although SH is usually seen as a solitary peripheral nodule less than 3 cm in diameter, multiple lesions have been reported in as many as 4% of all cases.2Devouassoux-Shisheboran M. Hayashi T. Linnoila R.I. Koss M.N. Travis W.D. A clinicopathologic study of 100 cases of pulmonary sclerosing hemangioma with immunohistochemical studies: TTF-1 is expressed in both round and surface cells, suggesting an origin from primitive respiratory epithelium.Am J Surg Pathol. 2000; 24: 906-916Crossref PubMed Scopus (264) Google Scholar The characteristic radiologic feature of SH is a well-defined nodule with good enhancement. We present the case of a patient with SH with an unusual air halo. A symptom-free 23-year-old man came to our clinic because of an abnormal shadow found on a chest radiographic film during military physical check-up. He reported unremarkable family and medical histories. Physical examination revealed no abnormal physical findings. Laboratory data were normal, including normal carcinoembryonic antigen and squamous cell carcinoma antigen levels. Computed tomography of the chest demonstrated a well-defined nodule (2.5 × 1.5 × 1.5 cm) in the anterior segment of the right upper lobe of the lung with moderate enhancement after injection of contrast agent. Emphysematous change in the pulmonary parenchyma surrounding the nodule was revealed under the setting of lung window (Figure 1). Magnetic resonance imaging of the chest revealed a well-defined, round nodule (2.3 × 1.7 × 1.7 cm) in the right upper lobe of the lung with higher T1- and T2-weighted signal intensities than seen in the adjacent muscles and mild enhancement after contrast injection. An air halo around the nodule was also identified (Figure 2). Bronchoscopy demonstrated no abnormality within visible range. Whole-body bone scan showed no evidence of metastasis. Surgical intervention was performed through a right posterolateral thoracotomy. Intraoperatively, a 2.5 × 1.5 × 1.5 cm, macroscopically grayish, soft mass was found. Wedge resection of the nodule was done. Because of much mucoid substances and nuclear atypia, a frozen-section diagnosis of non–small cell lung cancer was made and lobectomy of the right upper lobe with radical lymph node dissection was performed. Pathologic examination of permanent sections revealed pulmonary SH.Figure 2Magnetic resonance imaging of chest revealing air halo surrounding nodule (arrows).View Large Image Figure ViewerDownload Hi-res image Download (PPT) SH, a benign pulmonary neoplasm, occurs predominantly in middle-aged women.1Liebow A.A. Hubbell D.S. Sclerosing hemangioma (histiocytoma) of the lung.Cancer. 1956; 9: 53-75Crossref PubMed Scopus (279) Google Scholar, 2Devouassoux-Shisheboran M. Hayashi T. Linnoila R.I. Koss M.N. Travis W.D. A clinicopathologic study of 100 cases of pulmonary sclerosing hemangioma with immunohistochemical studies: TTF-1 is expressed in both round and surface cells, suggesting an origin from primitive respiratory epithelium.Am J Surg Pathol. 2000; 24: 906-916Crossref PubMed Scopus (264) Google Scholar SH is composed of four major histologic patterns: papillary, solid, hemorrhagic, and sclerotic. In one large series, a papillary pattern was observed in most cases of SH, and this tends to be the predominant type. Recent studies suggest that SH is derived from primitive respiratory epithelium.2Devouassoux-Shisheboran M. Hayashi T. Linnoila R.I. Koss M.N. Travis W.D. A clinicopathologic study of 100 cases of pulmonary sclerosing hemangioma with immunohistochemical studies: TTF-1 is expressed in both round and surface cells, suggesting an origin from primitive respiratory epithelium.Am J Surg Pathol. 2000; 24: 906-916Crossref PubMed Scopus (264) Google Scholar Although SH is considered a benign tumor, mediastinal lymph node metastasis has been noted in several case reports. The characteristic radiologic feature of SH is a well-defined nodule with good enhancement. Air meniscus sign, most commonly seen in aspergilloma, is uncommon but specific to SH. Bahk and colleagues3Bahk Y.W. Shinn K.S. Choi B.S. The air meniscus sign in sclerosing hemangioma of the lung.Radiology. 1978; 128: 27-29PubMed Google Scholar first described air-meniscus sign in a case of SH in 1978. Several cases of SH surrounded by air spaces have also been reported. Proliferation and hyalinization of undifferentiated alveolar mesenchymal cells may wrap around the bronchus and cause distention of the distal air space.3Bahk Y.W. Shinn K.S. Choi B.S. The air meniscus sign in sclerosing hemangioma of the lung.Radiology. 1978; 128: 27-29PubMed Google Scholar Peritumoral hemorrhage and tumor contraction, followed by communication of the airway, may be another mechanism for development of air meniscus sign.3Bahk Y.W. Shinn K.S. Choi B.S. The air meniscus sign in sclerosing hemangioma of the lung.Radiology. 1978; 128: 27-29PubMed Google Scholar Nam and associates4Nam J.E. Ryu Y.H. Cho S.H. Lee Y.J. Kim H.J. Lee D.Y. et al.Air-trapping zone surrounding sclerosing hemangioma of the lung.J Comput Assist Tomogr. 2002; 26: 358-361Crossref PubMed Scopus (26) Google Scholar have suggested that air meniscus sign, although an uncommon finding, is helpful in the differential diagnosis of SH from other benign tumors. Magnetic resonance imaging of the chest demonstrating an air halo surrounding SH has not previously been reported in the literature. The treatment of choice for SH is limited resection. The long-term survival after complete surgical resection is excellent.2Devouassoux-Shisheboran M. Hayashi T. Linnoila R.I. Koss M.N. Travis W.D. A clinicopathologic study of 100 cases of pulmonary sclerosing hemangioma with immunohistochemical studies: TTF-1 is expressed in both round and surface cells, suggesting an origin from primitive respiratory epithelium.Am J Surg Pathol. 2000; 24: 906-916Crossref PubMed Scopus (264) Google Scholar Preoperative cytologic study is often insufficient for diagnosis of SH. It may be also difficult to establish a definitive diagnosis by intraoperative frozen-section. Some reports have suggested that it is difficult to differentiate SH from bronchoalveolar cell carcinoma or metastatic papillary adenocarcinoma.5Wang S.E. Nieberg R.K. Fine needle aspiration cytology of sclerosing hemangioma of the lung, a mimicker of bronchioloalveolar carcinoma.Acta Cytol. 1986; 30: 51-54PubMed Google Scholar Expressions of thyroid transcription factor 1 and epithelial membrane antigen in round and surface cells of SH, accompanied by negative results of round cells for pancytokeratin, provide useful clues for the diagnosis of SH.2Devouassoux-Shisheboran M. Hayashi T. Linnoila R.I. Koss M.N. Travis W.D. A clinicopathologic study of 100 cases of pulmonary sclerosing hemangioma with immunohistochemical studies: TTF-1 is expressed in both round and surface cells, suggesting an origin from primitive respiratory epithelium.Am J Surg Pathol. 2000; 24: 906-916Crossref PubMed Scopus (264) Google Scholar Further studies are needed to elucidate the histogenesis and biologic behavior to aid in the diagnosis of SH. In our case, a false frozen-section diagnosis of non–small cell lung cancer was made because of the presence of copious mucoid substances and nuclear atypia. Lobectomy of the right upper lobe with radical lymph node dissection was therefore performed. Pathologic examination of permanent sections revealed pulmonary SH. The characteristic computed tomographic and magnetic resonance imaging features of SH may help with preoperative diagnosis and assessment. We are grateful to Dr Li Wing-Yin for his assistance with the pathologic diagnosis. We also thank Dr Wen-Juei Jeng for her contribution to this article.