A 24-year-old male presented to the hospital with four-day history of moderate left sided chest pain radiating to the back. The chest pain got worse with deep inspiration. He denied fever, chills, cough, hemoptysis, night sweats, weight loss, and recent travel. Past medical history was significant for three episodes of left lower lobe pneumonia in the past 6 months. He was treated initially with ceftibuten and azithromycin and then with a course of oral levofloxacin and most recently with amoxicillin-clavulanic acid for recurring symptoms of cough, pleuritic chest pain, and subjective fever. Currently, he was taking meloxicam as needed for chest pain. Past surgical history included right inguinal hernia repair five years ago. There was no family history of cancer, early death, or cardiac disease. He had immigrated from Guatemala four years ago and was single and unemployed. He denied any high-risk sexual behaviors or drug abuse in the present or past. He drank two beers about once or twice per week and denied smoking history. His differential diagnoses at this point include lung abscess, tuberculosis infection, foreign body aspiration, HIV with opportunistic infection, congenital immunodeficiency states, and congenital developmental anomaly of the lung.
On examination, he was tachycardic with a pulse rate of 101/min and was tachypneic at 22/min. Rest of the physical examination including respiratory examination was normal. Labs revealed complete blood counts of 14 x 109/L with 75% neutrophils. Basic metabolic panel and liver function tests were normal. Urine legionella antigen was negative, as well as antibodies to human immunodeficiency virus. His chest X-ray showed left lower lobe opacity. He was started on ceftriaxone and azithromycin for community acquired pneumonia and was admitted to the floor. Tuberculin skin test was positive with 18 mm induration at 72 hours. Interferon gamma release assay was negative. Blood cultures demonstrated no growth for 5 days.
CT angiogram of thorax showed 9 cm well-defined area of low attenuation in the left lower lobe (Figure 1) with infiltrates inside. This lesion demonstrated a dedicated pulmonary artery and pulmonary vein (Figure 2); these vessels were emerging from the hilar region. No systemic arteries or anomalous arterial supply was identified within the lesion. There was no pleural involvement or abnormal lymphadenopathy. A radiologic diagnosis of congenital pulmonary airway malformation (CPAM) was made. Review of previous chest X-rays and computed tomography (CT) of the thorax from the time of his previous episodes of pneumonia revealed various degrees of consolidation in left lower base in this particular area (Figure 3). CT abdomen pelvis did not show any abnormal intra-abdominal masses or pathology but showed some hepatic steatosis.
As his CT images were highly suggestive of congenital cystic lung lesion, surgical excision was planned to prevent further episodes of pneumonias. Bronchoscopy prior to the surgery revealed normal segmental airways in the left lower lobe. Initially left thoracoscopy was tried; however posterolateral thoracotomy was required for better visualization of the involved anatomy. Upon direct visualization, the complete lobe was involved in chronic inflammation. The lesion had no abnormal arterial supply from aorta or below the diaphragm and was connected through air passages. Left lower lobectomy was done. On gross examination, a relatively well-demarcated lesion with a 1.5 x 1.5 cm thin walled cyst with inspissated mucus within and multiple air filled microcysts at the peripheral aspect of the cyst was noted (Figure 4). Microscopic examination revealed larger cyst with columnar ciliated epithelium (Figure 5) and dispersed bronchiole-like structures within the alveolated parenchyma (Figure 6). The pathologic diagnosis was consistent with type 2 CPAM. There was no major surgical complication. He developed a small hydro pneumothorax postoperatively, which resolved on its own. Patient has been doing well 12 months after the diagnosis.