Infected Congenital Cystic Adenoid Malformation in an Adult

The Patient

In this video, the authors present the case of a minimally invasive resection of an infected CCAM in an adult. The patient is a twenty-nine-year-old African-American man who presented to the emergency department with shortness of breath and a productive green frothy cough for one and a half weeks. His past medical history was significant for asthma and left lower lobe congenital cystic adenoid malformation—in short, CCAM. He was diagnosed with CCAM at the age of five months and had been asymptomatic up to the point of his admissions. The patient had no significant past surgical history. He is a construction worker with an active smoking and substance abuse history. 

A complete workup was performed including blood work, respiratory cultures, and a CT scan which showed a 20 cm infected CCAM. CCAM is an adenomatous malformation that originates from the hyperplasia of bronchiolar epithelium resulting in numerous cysts formation. Unlike other congenital malformations, CCAM communicates with the tracheobronchial tree. It is the most common congenital airway anomaly and is more common in men. One-third of CCAMs are prenatally diagnosed. The incidence of CCAM ranges from one out of ten thousand to one out of thirty-five thousand pregnancies and it is very rare to diagnose CCAM in adults. CCAMs are also usually resected prenatally or within two years of age to allow compensatory lung expansion. 

When thinking about the reasons to resect CCAMs in adults, it is important to note that a good number of CCAMs in adults present with infection, and the risk of infection increases with age. It is also difficult to differentiate between CCAMs and malignancies in radiology. The presence of CCAMs also increases the risk of malignancy, which increases with age. 

The Surgery

To begin, the patient was immediately started on IV antibiotics and was taken to the operating room for definite management with a left lower lobectomy. The patient was intubated with a double-lumen endotracheal tube and placed in the right lateral decubitus position. Intercostal nerve blocks were performed for pain management. It is important to avoid epidurals for concern of spreading the infection to the nervous system. Next, a 5 mm port was placed in the seventh intercostal space in the posterior axillary line for the camera. A 12 mm port was placed one interspace above the diaphragm at the anterior axillary line. A 4 cm incision was made at the fourth intercostal space at the midaxillary line, and a wound protector was placed. 

After entering the thoracic cavity, the upper and lower lobes and the fissure were identified. The diaphragm and chest wall are identified to begin dissection. The dissection began by separating the left lower lobe from the chest wall and diaphragm. The inferior pulmonary ligament was identified and dissected and the anterior pleura was opened. Care was taken to prevent entry into the CCAM to avoid spillage and to reduce the risk of development of empyema. 

Next, the posterior pleura was opened. The subcarinal space was then identified and dissected. An endoscope was placed in the esophagus for proper identification and prevention of injury. The inferior pulmonary vein was then identified and dissected. A 45 mm tan load was used to divide the inferior pulmonary vein. Often, the lymph nodes may be enlarged and can be dissected for pathological evaluation of occult malignancies. The oblique fissure was divided for better exposure of the hilar structures. Multiple purple load staples may be required to achieve this goal. 

The next step was to identify the arterial structures for the left lower lobectomy. The superior segmental and basilar arteries were identified. The arteries were then carefully dissected. Tan load staples were used for the arterial divisions. Finally, the left lower lobe bronchus was dissected and subsequently divided. Cultures showed Strep anginosus. The patient was continued on ceftriaxone in the hospital and discharged on three weeks of Augmentin. Upon his one-month follow up, the patient returned to baseline activities.

In conclusion, infected CCAM should be surgically resected instead of chest tube placement to avoid bronchopleural fistulas. Care should be taken to avoid entry into CCAM and gross spillage to minimize the risk of empyema development. In case of a prolonged air leak, the affected parenchyma should be resected and a pleural tent can be performed with good outcomes.

References

1. Kagawa H, Miki K, Miki M, Urasaki K, Kitada S. Congenital cystic adenomatoid malformation in adults detected after infection. Respirol Case Rep. 2018 Sep 14;6(8):e00364. doi: 10.1002/rcr2.364. PMID: 30237885; PMCID: PMC6138539.
2. Dahabreh J, Zisis C, Vassiliou M, Arnogiannaki N. Congenital cystic adenomatoid malformation in an adult presenting as lung abscess. Eur J Cardiothorac Surg. 2000 Dec;18(6):720-3. doi: 10.1016/s1010-7940(00)00578-9. PMID: 11113682.

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