title: Epithelioid sarcoma presenting as pulmonary cysts with cancer antigen 125 expression.
abstract: A 39-year-old Japanese woman presented with a swollen right hand and a right-sided pneumothorax. Chest CT revealed bilateral multiple pulmonary thin-walled cysts measuring<or=1 cm in diameter and small nodules. An initial skin biopsy led to a misdiagnosis of metastatic adenocarcinoma, as tumour cells were positive for cytokeratin, epithelial membrane antigen, carcinoembryonic antigen and cancer antigen 125. However, chemotherapy proved ineffective, and the skin biopsy was repeated. A final diagnosis of epithelioid sarcoma (ES) was made. Open lung biopsy showed that the pulmonary nodules represented metastases of ES. Although the pulmonary cyst walls did not contain tumour cells, bronchiolar wall adjacent to the cysts had been infiltrated by tumour cells. These findings suggested that pulmonary cysts, a rare form of pulmonary metastases from soft tissue sarcomas, had developed through a ball-valve effect of metastatic tumour in small airways. However, presence of cancer antigen 125 hindered obtaining a correct diagnosis of ES.
authors.affiliation: First Department of Medicine, Hokkaido University Hospital and School of Medicine, Sapporo, Japan. eikik@med.hokudai.ac.jp
authors.forename: Eiki
authors.initials: E
authors.lastname: Kikuchi
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kinoshita
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamazaki
authors.forename: Tomoo
authors.initials: T
authors.lastname: Itoh
authors.forename: Tadamichi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shimizu
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nishimura
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000276:immunology / Q000473:pathology; D000328:Adult; D001706:Biopsy; D001994:Bronchogenic Cyst / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D018394:CA-125 Antigen / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D012509:Sarcoma / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D012867:Skin / Q000473:pathology
chemical_list: D018394:CA-125 Antigen