Discriminating Preoperative Features of Pleuropulmonary Blastomas (PPB) from Congenital Cystic Adenomatoid Malformations (CCAM): a Retrospective, Age-Matched Study

BACKGROUND: The etiopathogenesis of pleuropulmonary blastoma (PPB) and its relationship to congenital cystic adenomatoid malformation (CCAM) remain controversial. Our recent analysis indicates that both the co-incidental occurrence and the outcome of PPB among CCAM patients are significant. We report here on our efforts to determine clinical and radiological features discriminating PPB from CCAM preoperatively. MATERIALS & METHODS: A retrospective analysis of all patients treated for PPB and CCAM between 1981 and 2008 at 2 tertiary academic centers under a centralized, single payer healthcare system was performed (REB#1000013239). Clinical, radiological and demographic data were analyzed. PPB patients were secondarily age matched with CCAM patients (±10% age difference in months), and clinical, radiological and demographic variables were compared. Descriptive statistics and non-parametric analysis were used. RESULTS: A total of 10 PPB patients was identified. Median age at diagnosis was 24 months; the male to female ratio was 5:5. No PPB patients had an antenatal diagnosis (p<0.01). 9 were symptomatic, with symptoms including dyspnea (7/10), upper respiratory infection (6/10), poor weight gain (3/10), and 1 patient was asymptomatic. 5 of 10 patients had solid parts on CT, of which 4 out of 5 were diagnosed preoperatively as PPB and 1 out of 5 as CCAM. 5 of 10 were predominantly cystic of which none was diagnosed preoperatively as PPB (p=0.0476). Given that most CCAM patients are now diagnosed antenatally, only 5 PPB patients could be age-matched with CCAM patients. In the predominantly cystic PPB patients (n=5), no significant discriminating clinical and radiological features were identifiable when compared preoperatively with age-matched CCAM patients. CONCLUSION: PPB patients continue to represent a diagnostic challenge. Asymptomatic and predominantly cystic PPB remain indistinguishable from CCAM preoperatively. A high index of suspicion for PPB must be considered in any child presenting with cystic lung lesions beyond early infancy, particularly in a child with poor weight gain.