[Extralobar sequestration presenting increased serum CA19-9 and associated with lung aspergillosis--an unusual case].

In a thirty-four-year old man, an asymptomatic abnormal mass shadow was detected in S10 of the left lower lobe on chest X-ray film. The serum CA19-9 was abnormally elevated 395 U/ml). The definitive histological diagnosis was not obtained by both transbronchial and percutaneous lung biopsy preoperatively. Surgery demonstrated that an abnormal mass was separated from S10 of the left lower lobe by a fibrous tissue, and it contained severe inflammatory changes and abscess. Extralobar pulmonary sequestration was diagnosed, but aberrant arteries were not conformed. Sequestered lung and a part of the lower lobe were resected en bloc. The serum CA19-9 level returned to normal postoperatively. Aspergillus was only detected in the sequestered lung by postoperative cultre. Moreover, CA19-9 level in the fluid of this sequestered lung was markedly high, 50,000 U/ml. Production of CA19-9 was demonstrated in bronchial epithelium of the sequestered lung immunohistochemically. Extralobar pulmonary sequestration associated with aspergillosis and high serum CA19-9 is very rare. To our knowledge, this is the first reported case in the literatures.