The site of bronchogenic cysts depends on the stage of development when the malformation occurs. The most common site is thorax, for example, mediastinum (early in development), and lung (later in development). However, they have been reported in other sites such as neck, ileal mesentery, intradiafragmatic, intrapericardial, suprasellar, and laryngeal locations. These lesions may remain asymptomatic until they are picked on imaging for screening or otherwise [Figure 2]. Neck lesions are reported to be more common in males than in females (3- 4:1).[] Subcutaneous bronchogenic cysts are rare and are usually found in children as a small cystic lesion (<3 cm). Zheng et al. reported a 52-year-old woman presenting with a mass confirmed histologically as bronchogenic cyst in the left intergluteal cleft region.[] Rarely bronchogenic cysts can be located in the pericardial space. Intrapericardial cysts consist of 27% of the bronchogenic cysts and often difficult to diagnose even with newer imaging modalities.[] Intramural bronchogenic cysts of the esophagus are located in the upper mediastinum and are very rare.
Bronchogenic cysts are lined by pseudostratified columnar or cuboidal ciliated (respiratory) epithelium. The cyst wall often contains smooth muscle fibers, elastic fibers, submucosal bronchial glands, and hyaline cartilage. The cyst wall helps to distinguish them from other ciliated lined cysts such as foregut cyst, duplication cyst, and branchial cleft cyst. The role of cytology is crucial to properly triage such patients. Endoscopic ultrasound-guided fine-needle aspiration (EUSFNA) in the current case was consistent with ciliated lined cystic lesion without malignant cells [Figure 1]. The definitive diagnosis of bronchogenic cysts depends on histological examination of the surgical specimen with hyaline cartilage, bronchial glands, and/or smooth muscle in the wall of the lesion.
Complete removal of the cyst, especially if symptomatic due to possibility of complications in the future, is the preferred recommendation. Approximately 50% of bronchogenic cysts present with pain.[] Others may cause respiratory distress, cough, dyspnea, hemoptysis, dysphagia, nausea, vomiting, etc. Fever is a sign of infection and warrants a quick diagnosis with medical treatment and surgical removal as clinically indicated. Usually long-term prognosis with complete excision is assuring. However, incomplete excision may increase risk of recurrence.
The efficacy of EUS-FNA of cystic lesions partly depends on the site, size, and characteristics of the target tissue as well as on the expertise, training, and coordination between the procedure-performer and the cytology team.[] Acquisition of diagnostic samples is approached in different ways depending on the site and type of the lesion. Cytological samples are ideal for cyst fluid analysis, IHC, and molecular testing as indicated. As observed in the present case, the direct smears are invaluable, both for immediate assessment and also for the final morphological interpretation. The needle rinses can be processed as LBC and cell-block. Cell-block increases the diagnostic accuracy of EUS-FNA in general.[]
Bronchogenic cyst may be difficult to aspirate by TB-FNA, especially when the cyst content is thickly mucoid with debris. As observed in our case, intact ciliated cells could not be detected; however, there were many cell top fragments of the ciliated cells similar to ciliocytophthoria in Papanicolaou stained and Diff Quik stained direct smears [Figures 1 and 3]. These features would be relatively easily detectable in cytological preparations made with concentration methods such as LBC preparations including Surepath ,[] ThinPrep , and Cytospin . Malignant cells or granuloma were absent in our case. Cell-block also showed similar findings; however, relatively few ciliated cell fragments showed significantly inferior morphology as compared to that seen in cytology preparations [Figure 3].