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Cystic Lesions of the Thorax: Role of Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration

Twehues, Andrew MD; Islam, Shaheen MD

Journal of Bronchology & Interventional Pulmonology: July 2011 - Volume 18 - Issue 3 - p 265–268
doi: 10.1097/LBR.0b013e3182281063
Case Reports
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Traditional management of cystic lesions involving the mediastinum or lung parenchyma consists of surgical resection. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been reported to successfully treat bronchogenic cysts. We present 2 cases in which EBUS-TBNA was performed to aid in making the diagnosis. Endobronchial ultrasound imaging and TBNA were successful in both cases. The mediastinal cyst was therapeutically managed with complete aspiration in one case, whereas in the other an intraparenchymal cyst was found to be multiloculated and could only be partially aspirated and required surgical excision. EBUS-guided real-time aspiration of intrathoracic cysts can be both diagnostic and therapeutic in simple mediastinal bronchogenic cysts that can be fully aspirated. However, surgical resection may be required for multiloculated intraparenchymal cysts that cannot be aspirated completely. EBUS guidance helps to identify multiloculation and completeness of the aspiration.

Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, The Ohio State University Medical Center, Columbus, OH

Disclosure: No financial support was received for this work. The authors have no conflicts of interest to report.

Reprints: Shaheen Islam, MD, Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Ohio State University Medical Center, 473 West 12th Ave, 201 DHLRI, Columbus, OH 43210 (e-mail: Shaheen.islam@osumc.edu).

Received April 29, 2011

Accepted June 7, 2011

Cystic lesions of the mediastinum are uncommon and have a narrow differential. Bronchogenic cyst is included in this list. These cysts are rare congenital anomalies thought to result from the abnormal budding of the ventral foregut during development, which may later differentiate into a fluid-filled blind-ended pouch.1 Bronchogenic cysts can be mediastinal or intraparenchymal and can present with a wide spectrum of clinical presentation from being asymptomatic to producing acute respiratory distress.2–5 Radiographic manifestations vary widely as well.5

Parenchymal cystic lesions have a wider differential, including bronchogenic cyst, infection, malignant, benign or metastasizing neoplasm, and bronchopulmonary sequestration.

Traditional management of bronchogenic cysts has been surgical resection.2,6 Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been reported to successfully treat bronchogenic cysts.7–9 We present 2 cases where EBUS-TBNA was performed to aid in diagnosing the cystic lesion involving the thorax. In 1 case, the mediastinal cyst was therapeutically managed with EBUS-TBNA, and in the other the intraparenchymal multiloculated cyst required surgical excision.

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CASE REPORTS

Case 1

A 37-year-old woman with a history of intravenous drug use, 25 pack-years of smoking history, and previous latent tuberculosis treated with 9 months of isoniazid presented to her primary physician with fever, chills, chest pain, and cough. She was treated with an antibiotic for a possible pneumonia based on her chest radiograph. A computed tomography (CT) of the chest performed for the nonresolution of her symptoms revealed a 4×5.6 cm right paratracheal mass extending from the apex of the right lung to 2 cm above the main carina (Fig. 1). She did not have old radiologic studies to confirm its presence in the past. A repeat CT chest at 3 weeks showed a persistent right paratracheal mass. She underwent bronchoscopy with conventional transtracheal needle aspiration at a local hospital, which was unsuccessful. The patient was referred to our institution for possible biopsy and surgical resection of the undiagnosed mass. On account of her young age and reluctance to have surgery, EBUS-TBNA was considered. Using a linear probe EBUS scope (Olympus BF-UC160F-0L8, Olympus America Inc., Center Valley, PA), the ight paratracheal cystic lesion was visualized. A 22-gauge echogenic dimpled needle (NA-201SX-4022, Olympus America Inc., Center Valley, PA) was then inserted into the cystic mass under direct ultrasound guidance through the working channel of the EBUS scope. Approximately 150 mL of straw-colored fluid was withdrawn with repeated aspirations while the needle remained inside the mass. A postprocedure chest radiograph and the ultrasound image showed significant reduction of the mass. There was no purulence and the cytologic evaluation of the fluid yielded no malignant cells. Routine cultures grew upper airway contaminants, whereas acid fast bacilli culture and stain were negative. Repeat chest CT scan performed at 16 months confirmed stability of the lesion (Fig. 2).

FIGURE 1

FIGURE 1

FIGURE 2

FIGURE 2

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Case 2

A 54-year-old woman with a history of total abdominal hysterectomy in the remote past secondary to endometriosis presented to an outside hospital with chest pain and chronic cough present for 2 years. She was found to have an abnormal chest radiograph. A chest CT scan demonstrated a 4.3×5.7 cm well-circumscribed lesion in the left lower lobe (LLL) with fluid attenuation and septations suspicious for an intraparenchymal bronchogenic cyst (Fig. 3). The surrounding lung parenchyma was normal in appearance. The patient deferred further workup at that time. She continued to have persistent chest pain and cough and was referred to our institution. A repeat chest CT scan at 6 months revealed no change in the size of the lesion. Positron emission tomography showed no increase in the metabolic activity of the lesion. She underwent EBUS-TBNA. A linear probe EBUS scope (Olympus BF-UC160F-0L8; Olympus America Inc., Center Valley, PA) was placed in the LLL bronchus, which demonstrated a fluid-filled multiloculated lesion in the LLL (Fig. 4). Using a 22-gauge echogenic dimpled tip needle (NA-201SX-4022, Olympus America Inc., Center Valley, PA) through the working channel of the bronchoscope, 27 mL of straw-colored fluid was withdrawn from one septation and 33 mL was drawn from another, under real-time ultrasound guidance. Further septations were recognized by ultrasound. However, after repeated attempts no further fluid could be aspirated. The aspirated fluid was without purulence, and microbiology (routine, fungal, mycobacterial) and cytology were all negative. Postprocedure chest CT scan showed minimal reduction in the size of the lesion. Video-assisted thorascopic surgery with left lower lobectomy was performed. The pathology revealed a smooth muscle neoplasm consistent with benign metastasizing leiomyoma (BML).

FIGURE 3

FIGURE 3

FIGURE 4

FIGURE 4

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DISCUSSION

Bronchogenic cysts in adults occasionally present as an asymptomatic radiographic finding, unlike our first patient who had constitutional symptoms. Conservative management with radiologic follow-up is controversial, given the higher morbidity and mortality associated with late surgical excision felt to be secondary to cyst growth and adhesion to surrounding structures.6 Definitive treatment of bronchogenic cysts traditionally has been surgical excision, given the possibility for recurrence. With the rare chance for malignant transformation, surgical excision also confirms diagnosis with adequate pathologic assessment.10 Case reports have recommended conservative management with intermittent conventional TBNA in patients with bronchogenic cyst with minimal symptoms or in those reluctant or unable to undergo surgery.7,8 Neither of our patients had old chest imaging to confirm the congenital nature of the lesions. We did entertain a possibility of infectious etiology with case 1, given her history of intravenous drug use and associated fever and the evidence of an infiltrate on chest CT scan. All cultures, including those for acid fast bacilli from the aspirated fluid, were negative. Chest CT scan at 9 and 16 months after EBUS-TBNA showed complete resolution of the cyst and she has remained asymptomatic even at the 19th month. We plan to follow her with serial imaging to document any change in size, shape, or character of the lesion and to reserve surgical excision only if her symptoms return.

Our first case had an unsuccessful aspiration using conventional transtracheal needle aspiration at a local hospital. Noting the size and location of the lesion, it is likely that conventional TBNA would have been equally successful in the hands of skilled personnel, given that there were no loculations. Furthermore, theoretically there is the option to use a larger 19-gauge needle with the conventional technique. We decided to use real-time ultrasound guidance in the first case because of the previous failed attempt at a local hospital.

The potential causes of failure to aspirate a similar paratracheal cystic lesion could be a result of one or a combination of more than one of the following factors: (1) the needle is directed rather parallel to the trachea and not perpendicular to the tracheal wall; (2) the needle is introduced along the peripheral aspect of the lesion and the needle tip is either in the soft tissue of the mediastinum or in the lung parenchyma; (3) without an anatomic landmark nearby (especially in high paratracheal location), it may be difficult to maintain orientation and it is possible that the needle is directed anterior, posterior, superior, or inferior to the lesion; (4) inadequate sedation with coughing may prevent appropriate placement of the needle; (5) a small 22-gauge needle tip may be occluded with blood clot or even with a piece of tracheal cartilage during insertion; (6) inadequate suction is applied or it is not completely airtight; and (7) presence of loculations.

In contrast, conventional TBNA was not an appropriate approach in the second case because of the septated nature and location of the cyst deep within the parenchyma of the LLL. It is difficult to bend the tip of a regular bronchoscope inside the smaller bronchus to achieve the appropriate angle to direct the needle laterally through the airway wall. In the convex probe EBUS scope (Olympus BF-UC160F-0L8; Olympus America Inc., Center Valley, PA), the needle exits slightly more laterally at an approximately 20-degree angle with respect to the axis of the bronchoscope. This allows the needle to go more perpendicular to the airway wall for easier sampling of parenchymal lesions located away from the airways. In addition, the length of a dedicated EBUS needle (NA-201SX-4022, Olympus America Inc., Center Valley, PA) is 40 mm, which permits aspiration from a deeper lesion that cannot be reached with a conventional needle, which is only approximately 15 mm long.

Occasionally, bronchogenic cysts may be loculated and the conventional TBNA may not be completely successful. We recommend that all loculated cystic lesions (mediastinal or parenchymal) should be aspirated with real-time EBUS guidance, as it allows proper needle placement and the progress of aspiration can be observed in real time. With complete aspiration of a simple or even loculated mediastinal cyst with EBUS-TBNA, it is hypothesized that apposition of the mucosal lining may lead to adhesion preventing recurrence.4

Incidentally, we sent our second patient for surgical resection because all the septations of the cyst could not be drained completely with repeated attempts under real-time ultrasound guidance. It is possible that after the initial aspiration there was bleeding inside the cyst, and a blood clot prevented further aspiration through the smaller 22-gauge needle. We do not think that the viscosity of the cystic fluid was a contributing factor as we were able to drain other 2 septations easily. Our concern was that even if this was an intraparenchymal cyst, without complete aspiration recurrence or persistence of her symptoms was likely. In addition, the concern for neoplasm was not totally alleviated after our procedure. Incomplete aspiration of an intraparenchymal cyst such as this may leave a persistent structural abnormality, which could be a nidus for infection.

It is interesting to note that, our second patient was found to have a rare BML presumably of uterine origin, which is even rarer given its cystic nature.11,12 Pulmonary BML has been reported in patients who have undergone hysterectomy for uterine leiomyoma,12 although the pathogenesis is controversial. Her hysterectomy was because of endometriosis. Although benign in nature, BML has been documented to compress surrounding parenchyma causing mechanical distortion and dysfunction requiring surgical intervention.13 In this case, surgery was both diagnostic and therapeutic.

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CONCLUSIONS

EBUS-guided real-time aspiration of cystic lesions can be both diagnostic and therapeutic, especially in mediastinal bronchogenic cysts that can be fully aspirated. Bronchoscopic needle aspiration with appropriate follow-up is a viable alternative to surgery in patients with a mediastinal bronchogenic cyst. BML, although rare may present as an intraparenchymal cyst. EBUS-TBNA provides an advantage over conventional TBNA by allowing better imaging of loculated cysts that may not be appreciated on chest CT scan. It also permits appropriate placement of needle in each loculation to drain them individually and assuring completeness of aspiration. Surgical resection should be reserved for intraparenchymal bronchogenic cysts that cannot be drained completely or if the pathology is in doubt.

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REFERENCES

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9. Casal RF, Jimenez CA, Mehran RJ, et al. Infected mediastinal bronchogenic cyst successfully treated by endobronchial ultrasound-guided fine-needle aspiration. Ann Thorac Surg. 2010:90e52–90e53
10. Merchan J, Loscertales C, Valera G, et al. Resection of 8 mediastinal bronchogenic cysts by video-assistend thoracoscopy. Arch Bronconeumol. 2008;44:220–223
11. Bachman D, Wolff M. Pulmonary metastases from benign-appearing smooth muscle tumors of the uterus. AJR Am J Roentgenol. 1976;127:441–446
12. Hoetzenecker K, Ankersmit HJ, Aigner C, et al. Consequences of a wait-and-see strategy for benign metastasizing leiomyomatosis of the lung. Ann Thorac Surg. 2009;87:613–614
13. Abramson S, Gilkeson R, Goldstein J, et al. Benign metastasizing leiomyoma: clinical, imaging and pathologic correlation. AJR Am J Roentgenol. 2001;176:1409–1413
Keywords:

bronchogenic cyst; EBUS; endobronchial ultrasound; therapeutic; thoracic cyst; TBNA; benign metastasizing leiomyoma

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