Cerebral metastasis and other central nervous system complications of pleuropulmonary blastoma

Pleuropulmonary blastoma (PPB) is a rare tumor of pleura and lung in young children. Central nervous system (CNS) complications, particularly cerebral parenchymal metastases, occur in aggressive forms of PPB: Types II and III PPB. This article evaluates cerebral and meningeal metastases, cerebrovascular events (CVA) caused by tumor emboli, spinal cord complications, and intracranial second malignancies in PPB.

International PPB Registry and literature cases were evaluated for CNS events. Cerebral metastasis patients were evaluated for gender, side of origin of PPB, PPB Type, interval from diagnosis to metastasis, status of chest disease, treatment, and outcome. Standard statistical methods were used to calculate the cumulative probability of cerebral metastasis and survival following metastasis.

Thirty-nine cases of cerebral metastasis were identified in 5/53 Registry Type II cases, 15/44 Registry Type III cases, and 19/143 literature Type II/III cases. Metastases occurred 1-60, median 11.5 months after diagnosis. Chest disease was controlled in 50% of children at time of metastasis. The cumulative probability of cerebral metastasis by 5 years from diagnosis was 11% for Type II patients (95%CI (confidence interval): 2-20%) and 54% for Type III patients (95%CI: 31-76%). Seven children survive cerebral metastasis. Other CNS complications were post-operative CVA (five cases), spinal cord invasion or compression (six), leptomeningeal disease (three), and second intracranial malignancies (two).

Cerebral metastasis is more frequent in PPB than in other childhood sarcomas. Clinicians should screen for this complication. Diverse other CNS complications are less common and require careful diagnosis.