Pediatric pleuropulmonary blastoma: analysis of four cases.

Background: Pleuropulmonary Blastoma (PPB) is an extremely uncommon, highly aggressive tumor that arises from either the lungs or pleura. According to Dehner, PPB was classified into three groups: type I (cystic), type II (mixed), and type III (solid). Type I tends to occur more commonly in infants and has a more favorable prognosis compared to types II and III. This tumor is very rare in pediatric age group; hence, there is no consensus on the optimal treatment regimen for it to date. Type I tumors, which resemble congenital lung cysts, can eventually progress to more aggressive type II and type III tumors. This article aims to increase general awareness of this pathology, clinical presentation, and differential diagnosis in order to identify this rare entity early in its course. By presenting 4 such cases, we highlight that PPB can be missed early in diagnosis and it is important to be alert when putting this rare tumor in differential diagnosis of cystic lung lesions.

Methods: A retrospective study was conducted between 2015 and 2020 involving patients who had a definitive diagnosis of PPB with emphasis on clinical presentation, preoperative imaging studies, intra-operative findings, pathological reports, ancillary treatment, and outcomes. All patients were followed up every 6 months to monitor local recurrence and distant metastasis by undergoing physical exam and non-contrast enhanced CT of the chest. The primary outcome is to identify the mortality and morbidity (recurrence and distant metastasis) of PPB for cases admitted in our institute.

Results: Four children were diagnosed with PPB during the study period. Clinically, patients presented with manifestations ranging from respiratory distress, fever to obstructive shock and radiologically, 2 cases were presented with mediastinal mass and the other 2 presented with pneumothorax. Regrettably, none of the cases were diagnosed pre-operatively. One lesion proved to be type I, 2 were type II and one was type III. All cases underwent chemotherapy using the combination of vincristine, Adriamycin and cyclophosphamide (VAC regimen). Recurrence was detected in a type II case, around 2 years after operation, and the other type II case developed brain metastasis that was discovered 3 years after operation. Type I case showed no local or distant metastasis.

Conclusion: A prompt preoperative diagnosis and workup of cases of PPB is crucial to enable optimal intervention intraoperatively and early postoperative treatment. Though it is uncommon, PPB should be considered in the differential diagnosis of cystic lung lesions.