INTRODUCTION: Congenital pulmonary airway malformation (CPAM), previously known as adenomatiod malformation (CCAM), is a rare developmental anomaly of the airways. Respiratory distress in neonates is the most common clinical presentation. It may however, remain asymptomatic until later in life despite having large bulla. There are five types of CPAM. Type 1 is most common and has potential for malignant transformation, which is poorly described in the literature. We present a case of incidental diagnosis of CPAM type 1 with malignant transformation in a 51-year-old man.
CASE PRESENTATION: A 51-year-old man, never smoker, was initially diagnosed with left sided congenital lobar emphysema at age eleven. When he was 27 years old, he developed a pneumothorax following trauma for which tube thoracostomy was required. He remained asymptomatic thereafter with stable radiological findings and pulmonary function. However, fourteen years later he developed arthritis and intrathoracic lymphadenopathy diagnosed as sarcoidosis by mediastinoscopic lymph node biopsy. Plaquanil and steroids provided symptomatic relief. At age 51, presented with upper respiratory tract infection associated with chest pain. Chest xray showed a large left sided bulla. Chest tomography confirmed a large left sided pneumothorax with associated left upper and lower lobe compressive collapse, and large lung bulla measuring 14.0x 11.0x 9.5 cm. A pigtail catheter with a Heimlich valve was placed. Unfortunately, the pneumothorax worsened causing mediastinal shift and significant respiratory distress. This lead to a left sided video assisted thoracoscopy, bullectomy, adhesiolysis, and doxycycline pleurodesis. The histopathology showed primitive bronchiolar type epithelium lining a large cyst spaces with foci of visceral pleura, chronic pleuritis, and adhesions. In scattered foci throughout the specimen, there was atypical mucinous epithelium, which was consistent with a mucinous bronchioloalveolar cell carcinoma.
DISCUSSION: CPAM type 1 is a non-heritable bronchopulmonary malformation resulting from anomalous branching morphogenesis of the lungs. It has been postulated that CPAM originates from proximal to distal bronchioles. It has been described as a 2 to 10 cm thin walled cyst lined with pseudostratified columnar epithelium, elastic tissue, and smooth muscle usually involving one lobe of the lung. This entity most often presents with respiratory distress in neonates and children but can remain asymptomatic until later in life. However, there are very few cases reported in adults. Definitive treatment is surgical resection to prevent recurrent infection and malignant transformation. Differential diagnosis for CPAM includes bronchopulmonary sequestration and congenital lobar emphysema. CPAM type 1 is rarely associated with malignancy. This patient’s CPAM type 1 underwent malignant transformation into mucinous bronchioloalveolar carcinoma which is a rarely reported occurrence.
CONCLUSIONS: The case illustrates an adulthood presentation of CPAM type 1 with its’ malignant transformation potential.
Reference #1 Albers,GM,Wood,RE.Update in the diagnosis and management of congenital malformations of the airway and lung. Clin pulm Med 1995;2:368
Reference #2 Priest,JR, Williams,GM,Hill,DA,et al. Pulmonary cysts in early childhood and the risk of malignancy. Pediatr Pulmonol 2009;44:14
Reference #3 West,D,Nichholson,AG,Colquhoun,I,Pollock,J.Bronchioloalveolar carcinomain congenital cystic adenomatoid malformation of lungs. Ann Thorac Surg 2007;83:687
DISCLOSURE: The following authors have nothing to disclose: Ashish Maskey, Numaan Mallik, Sudish Murthy, Carol Farver, Francisco Almeida
No Product/Research Disclosure Information