Non-infected and Infected Bronchogenic Cyst: The Correlation of Image Findings with Cyst Content
A 51-year-old woman without a significant medical history presented to our hospital complaining of chest pain lasting 2 months. She was a non-smoker. Chest CT revealed a rounded lesion, 2.3 cm in maximum diameter, with homogeneous soft-tissue attenuation density. The lesion was located at the right lower paraesophageal space (). The physical examination and results of routine laboratory tests were normal. We performed bronchoscopic US (CP-EBUS, BF-UC260F-OL8; Olympus, Tokyo, Japan) via the transesophageal route to characterize the lesion. A dedicated ultrasound scanner (EU-C2000; Olympus) was used as the image processor. US depicted a 2.3-cm, round, hypoechoic lesion with some fine homogenous internal echoes and the absence of a Doppler flow signal (). To rule out a malignant lymphadenopathy, transesophageal fine-needle aspiration (FNA) biopsy was performed with a 22-gauge needle (Olympus NA-202C, 4 passes) under bronchoscopic US guidance. Whitish jelly-milk-like content was aspirated (), fluid cytology showed no evidence of malignancy and Gram staining and cultures of the mucous content showed no organisms. Fever, chest pain, and dysphagia developed within a few days thereafter, and leukocytosis was noted. Cystic infection was suspected, but to rule out other serious complications such as mediastinitis, chest MRI was performed and intravenous administration of antibiotics (ampicillin/sulbactam, 3 g q 8 hr) was begun. The cystic lesion increased in maximum diameter from 2.3 cm to 2.6 cm. Upon contrast-enhanced MRI, a T1WI showed low signal intensity, and a T2WI showed heterogeneous high signal intensity, no enhancement of the cyst contents, but enhancement of the thickened cystic wall (). The patient underwent video-assisted thoracic surgery (VATS) 14 days after the FNA. The cystic mass was completely removed, and the aspirate was yellowish and turbid (). The resection specimen consisted of a benign cyst with a respiratory-type epithelial lining, smooth muscle, and epithelial denudation with infiltration of neutrophils and lymphocytes. The findings favored a diagnosis of bronchogenic cyst with active inflammation (). The MRI findings, the change in the cyst contents, and the pathology findings suggested that a secondary infection occurred after the FNA. Cultures of the aspirate were negative, probably because VATS was performed after 12 days of antibiotic therapy. The postoperative course was unremarkable. The patient's symptoms improved within a few days after the surgery, and no recurrence was seen upon follow-up chest CT at 8 months.